All sqpoll rings (even sharing sqpoll task) are currently dead bound
to the task that created them, iow when owner task dies it kills all
its SQPOLL rings and their inflight requests via task_work infra. It's
neither the nicist way nor the most convenient as adds extra
locking/waiting and dependencies.
Leave it alone and rely on SIGKILL being delivered on its thread group
exit, so there are only two cases left:
1) thread group is dying, so sqpoll task gets a signal and exit itself
cancelling all requests.
2) an sqpoll ring is dying. Because refs_kill() is called the sqpoll not
going to submit any new request, and that's what we need. And
io_ring_exit_work() will do all the cancellation itself before
actually killing ctx, so sqpoll doesn't need to worry about it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3cd7f166b9c326a2c932b70e71a655b03257b366.1619389911.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After closing an SQPOLL ring, io_ring_exit_work() kicks in and starts
doing cancellations via io_uring_try_cancel_requests(). It will go
through io_uring_try_cancel_iowq(), which uses ctx->tctx_list, but as
SQPOLL task don't have a ctx note, its io-wq won't be reachable and so
is left not cancelled.
It will eventually cancelled when one of the tasks dies, but if a thread
group survives for long and changes rings, it will spawn lots of
unreclaimed resources and live locked works.
Cancel SQPOLL task's io-wq separately in io_ring_exit_work().
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a71a7fe345135d684025bb529d5cb1d8d6b46e10.1619389911.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The variable up.resv is not initialized and is being checking for a
non-zero value in the call to _io_register_rsrc_update. Fix this by
explicitly setting the variable to 0.
Addresses-Coverity: ("Uninitialized scalar variable)"
Fixes: c3bdad0271 ("io_uring: add generic rsrc update with tags")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210426094735.8320-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With dynamic buffer updates, registered buffers in the table may change
at any moment. First of all we want to prevent future races between
updating and importing (i.e. io_import_fixed()), where the latter one
may happen without uring_lock held, e.g. from io-wq.
Save the first loaded io_mapped_ubuf buffer and reuse.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/21a2302d07766ae956640b6f753292c45200fe8f.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of keeping a table of ubufs convert them into pointers to ubuf,
so we can atomically read one pointer and be sure that the content of
ubuf won't change.
Because it was already dynamically allocating imu->bvec, throw both
imu and bvec into a single structure so they can be allocated together.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b96efa4c5febadeccf41d0e849ac099f4c83b0d3.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new io_uring_register() opcode for rsrc registeration. Instead of
accepting a pointer to resources, fds or iovecs, it @arg is now pointing
to a struct io_uring_rsrc_register, and the second argument tells how
large that struct is to make it easily extendible by adding new fields.
All that is done mainly to be able to pass in a pointer with tags. Pass
it in and enable CQE posting for file resources. Doesn't support setting
tags on update yet.
A design choice made here is to not post CQEs on rsrc de-registration,
but only when we updated-removed it by rsrc dynamic update.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c498aaec32a4bb277b2406b9069662c02cdda98c.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need a way to notify userspace when a lazily removed resource
actually died out. This will be done by associating a tag, which is u64
exactly like req->user_data, with each rsrc (e.g. buffer of file). A CQE
will be posted once a resource is actually put down.
Tag 0 is a special value set by default, for whcih it don't generate an
CQE, so providing the old behaviour.
Don't expose it to the userspace yet, but prepare internally, allocate
buffers, add all posting hooks, etc.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2e6beec5eabe7216bb61fb93cdf5aaf65812a9b0.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
REQ_F_INFLIGHT deaccounting doesn't do any spinlocking or resource
freeing anymore, so it's safe to move it into the normal cleanup flow,
i.e. into io_clean_op(), so making it cleaner.
Also move io_req_needs_clean() to be first in io_dismantle_req() so it
doesn't reload req->flags.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/90653a3a5de4107e3a00536fa4c2ea5f2c38a4ac.1618916549.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[ 736.982891] INFO: task iou-sqp-4294:4295 blocked for more than 122 seconds.
[ 736.982897] Call Trace:
[ 736.982901] schedule+0x68/0xe0
[ 736.982903] io_uring_cancel_sqpoll+0xdb/0x110
[ 736.982908] io_sqpoll_cancel_cb+0x24/0x30
[ 736.982911] io_run_task_work_head+0x28/0x50
[ 736.982913] io_sq_thread+0x4e3/0x720
We call io_uring_cancel_sqpoll() one by one for each ctx either in
sq_thread() itself or via task works, and it's intended to cancel all
requests of a specified context. However the function uses per-task
counters to track the number of inflight requests, so it counts more
requests than available via currect io_uring ctx and goes to sleep for
them to appear (e.g. from IRQ), that will never happen.
Cancel a bit more than before, i.e. all ctxs that share sqpoll
and continue to use shared counters. Don't forget that we should not
remove ctx from the list before running that task_work sqpoll-cancel,
otherwise the function wouldn't be able to find the context and will
hang.
Reported-by: Joakim Hassila <joj@mac.com>
Reported-by: Jens Axboe <axboe@kernel.dk>
Fixes: 37d1e2e364 ("io_uring: move SQPOLL thread io-wq forked worker")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1bded7e6c6b32e0bae25fce36be2868e46b116a0.1618752958.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Colin reported before possible overflow and sign extension problems in
io_provide_buffers_prep(). As Linus pointed out previous attempt did nothing
useful, see d81269fecb ("io_uring: fix provide_buffers sign extension").
Do that with help of check_<op>_overflow helpers. And fix struct
io_provide_buf::len type, as it doesn't make much sense to keep it
signed.
Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: efe68c1ca8 ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/46538827e70fce5f6cdb50897cff4cacc490f380.1618488258.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't fail submission attempts if there are CQEs in the overflow
backlog, but give away the decision making to the userspace. It
might be very inconvenient to the userspace, especially if
submission and completion are done by different threads.
We can remove it because of recent changes, where requests
are now not locked by the backlog, backlog entries are allocated
separately, so they take less space and cgroup accounted.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A hand-edit while applying this patch on top of a new base resulted in
a reverted check for re-issue, resulting in spurious -EAGAIN errors.
Fixes: 8c130827f4 ("io_uring: don't alter iopoll reissue fail ret code")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We manage these separately right now, just tie it to the request lifetime
and make it be part of the usual REQ_F_NEED_CLEANUP logic.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have this in two spots right now, which is a bit fragile. In
preparation for moving REQ_F_POLLED cleanup into the same spot, move
the check into a separate helper so we only have it once.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The re-add handling isn't correct for the multi wait case, so let's
just disable it for now explicitly until we can get that sorted out. This
just turns it into a one-shot request. Since we pass back whether or not
a poll request terminates in multishot mode on completion, this should
not break properly behaving applications that check for IORING_CQE_F_MORE
on completion.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[ 245.463317] INFO: task iou-sqp-1374:1377 blocked for more than 122 seconds.
[ 245.463334] task:iou-sqp-1374 state:D flags:0x00004000
[ 245.463345] Call Trace:
[ 245.463352] __schedule+0x36b/0x950
[ 245.463376] schedule+0x68/0xe0
[ 245.463385] __io_uring_cancel+0xfb/0x1a0
[ 245.463407] do_exit+0xc0/0xb40
[ 245.463423] io_sq_thread+0x49b/0x710
[ 245.463445] ret_from_fork+0x22/0x30
It happens when sqpoll forgot to run park_task_work and goes to exit,
then exiting user may remove ctx from sqd_list, and so corresponding
io_sq_thread() -> io_uring_cancel_sqpoll() won't be executed. Hopefully
it just stucks in do_exit() in this case.
Fixes: dbe1bdbb39 ("io_uring: handle signals for IO threads like a normal thread")
Reported-by: Joakim Hassila <joj@mac.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Having poll update function as a part of IORING_OP_POLL_ADD is not
great, we have to do hack around struct layouts and add some overhead in
the way of more popular POLL_ADD. Even more serious drawback is that
POLL_ADD requires file and always grabs it, and so poll update, which
doesn't need it.
Incorporate poll update into IORING_OP_POLL_REMOVE instead of
IORING_OP_POLL_ADD. It also more consistent with timeout remove/update.
Fixes: b69de288e9 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Isolate poll mask SQE parsing and preparations into a new function,
which will be reused shortly.
Fixes: b69de288e9 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't allow REQ_OP_POLL_REMOVE to kill apoll requests, users should not
know about it. Also, remove weird -EACCESS in io_poll_update(), it
shouldn't know anything about apoll, and have to work even if happened
to have a poll and an async poll'ed request with same user_data.
Fixes: b69de288e9 ("io_uring: allow events and user_data update of running poll requests")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't reinit io_ring_exit_work()'s exit work/completions on each
iteration, that's wasteful. Also add list_rotate_left(), so if we failed
to complete the task job, we don't try it again and again but defer it
until others are processed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only way to get out of io_iopoll_getevents() and continue iterating
is to have empty iopoll_list, otherwise the main loop would just exit.
So, instead of the unlock on 8th time heuristic, do that based on
iopoll_list.
Also, as no one can add new requests to iopoll_list while
io_iopoll_check() hold uring_lock, it's useless to spin with the list
empty, return in that case.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5b8ebe84f5fff7ffa1f708952dfef7fc78b668e2.1618278933.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As CQE overflows are now untied from requests and so don't hold any
ref, we don't need to handle exiting/exec'ing cases there anymore.
Moreover, it's much nicer in regards to userspace to save overflowed
CQEs whenever possible, so remove failing on in_idle.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d873b7dab75c7f3039ead9628a745bea01f2cfd2.1618278933.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't save return values of hrtimer_try_to_cancel() in a variable, but
use right away. It's in general safer to not have an intermediate
variable, which may be reused and passed out wrongly, but it be
contracted out. Also clean io_timeout_extract().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d2566ef7ce632e6882dc13e022a26249b3fd30b5.1618278933.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If io_sqe_files_unregister() faults on io_rsrc_ref_quiesce(), it will
fail to do unregister leaving files referenced. And that may well happen
because of a strayed signal or just because it does allocations inside.
In io_ring_ctx_free() do an unsafe version of unregister, as it's
guaranteed to not have requests by that point and so quiesce is useless.
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e696e9eade571b51997d0dc1d01f144c6d685c05.1618278933.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Revert of revert of "io_uring: wait potential ->release() on resurrect",
which adds a helper for resurrect not racing completion reinit, as was
removed because of a strange bug with no clear root or link to the
patch.
Was improved, instead of rcu_synchronize(), just wait_for_completion()
because we're at 0 refs and it will happen very shortly. Specifically
use non-interruptible version to ignore all pending signals that may
have ended prior interruptible wait.
This reverts commit cb5e1b8130.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7a080c20f686d026efade810b116b72f88abaff9.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req_set_fail_links() condition checking is bulky. Even though it's
always in a slow path, it's inlined and generates lots of extra code,
simplify it be moving HARDLINK checking into helpers killing linked
requests.
text data bss dec hex filename
before: 79318 12330 8 91656 16608 ./fs/io_uring.o
after: 79126 12330 8 91464 16548 ./fs/io_uring.o
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/96a9387db658a9d5a44ecbfd57c2a62cb888c9b6.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't need to store file tables in rsrc nodes, for now it's easier to
handle tables not generically, so move file tables into the context. A
nice side effect is having one less pointer dereference for request with
fixed file initialisation.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/de9fc4cd3545f24c26c03be4556f58ba3d18b9c3.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for more changes do a little cleanup of
io_sqe_buffers_register(). Move all args/invariant checking into it from
io_buffers_map_alloc(), because it's confusing. And add a bit more
cleaning for the loop.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/93292cb9708c8455e5070cc855861d94e11ca042.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Randy reports the following error on CONFIG_BLOCK not being set:
../fs/io_uring.c: In function ‘kiocb_done’:
../fs/io_uring.c:2766:7: error: implicit declaration of function ‘io_resubmit_prep’; did you mean ‘io_put_req’? [-Werror=implicit-function-declaration]
if (io_resubmit_prep(req)) {
Provide a dummy stub for io_resubmit_prep() like we do for
io_rw_should_reissue(), which also helps remove an ifdef sequence from
io_complete_rw_iopoll() as well.
Fixes: 8c130827f4 ("io_uring: don't alter iopoll reissue fail ret code")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are three cases where we much care about performance of
io_cqring_fill_event() -- flushing inline completions, iopoll and
io_req_complete_post(). Inline a hot part of fill_event() into them.
All others are not as important and we don't want to bloat binary for
them, so add a noinline version of the function for all other use
use cases.
nops test(batch=32): 16.932 vs 17.822 KIOPS
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a11d59424bf4417aca33f5ec21008bb3b0ebd11e.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Take advantage of delayed/inline completion flushing and pass right
issue flags for completion of open, open2, fadvise and poll remove
opcodes. All others either already use it or always punted and never
executed inline.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0badc7512e82f7350b73bb09abbebbecbdd5dab8.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of keeping requests in a inflight_list, just track them with a
per tctx atomic counter. Apart from it being much easier and more
consistent with task cancel, it frees ->inflight_entry from being shared
between iopoll and cancel-track, so less headache for us.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3c2ee0863cd7eeefa605f3eaff4c1c461a6f1157.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
hash_del() works well with non-hashed nodes, there's no need to check
if it is hashed first.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove error parameter from io_poll_complete(), 0 is always passed,
and do a bit of cleaning on top.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_poll_complete() always fills an event (even an overflowed one), so we
always should do io_cqring_ev_posted() afterwards. And that's what is
currently happening, because second EPOLLONESHOT check is always true,
it can't return !done for oneshots.
Remove those branching, it's much easier to read.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently allow racy updates to multishot requests, but we can end up
double adding the poll request if both completion and update does it.
Ensure that we skip re-add on the update side if someone else is
completing it.
Fixes: b69de288e9 ("io_uring: allow events and user_data update of running poll requests")
Reported-by: Joakim Hassila <joj@mac.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add struct io_fixed_file representing a single registered file, first to
hide ugly struct file **, which may be misleading, and secondly to
retype it to unsigned long as conversions to it and back to file * for
handling and masking FFS_* flags are getting nasty.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/78669731a605a7614c577c3de552631cfaf0869a.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Introduce a heler io_free_file_tables() doing all the cleaning, there
are several places where it's hand coded. Also move all allocations into
io_sqe_alloc_file_tables() and rename it, so all of it is in one place.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/502a84ebf41ff119b095e59661e678eacb752bf8.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't put linked timeout req in io_async_find_and_cancel() but do it in
io_link_timeout_fn(), so we have only one point for that and won't have
to do it differently as it's now (put vs put_deferred). Btw, improve a
bit io_async_find_and_cancel()'s locking.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d75b70957f245275ab7cba83e0ac9c1b86aae78a.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace a hand-coded overflow check with a specialised function. Even
though compilers are smart enough to generate identical binary (i.e.
check carry bit), but it's more foolproof and conveys the intention
better.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e437dcdc929bacbb6f11a4824ecbbf17225cb82a.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
rsrc_data refs should always be valid for potential submitters,
io_rsrc_ref_quiesce() restores it before unlocking, so
percpu_ref_is_dying() check in io_sqe_files_unregister() does nothing
and misleading. Concurrent quiesce is prevented with
struct io_rsrc_data::quiesce.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bf97055e1748ee3a382e66daf384a469eb90b931.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're going to ever support multiple types of resources we need
shared rsrc nodes to not bloat requests, that is implemented in this
patch. It also gives a nicer API and saves one pointer dereference
in io_req_set_rsrc_node().
We may say that all requests bound to a resource belong to one and only
one rsrc node, and considering that nodes are removed and recycled
strictly in-order, this separates requests into generations, where
generation are changed on each node switch (i.e. io_rsrc_node_switch()).
The API is simple, io_rsrc_node_switch() switches to a new generation if
needed, and also optionally kills a passed in io_rsrc_data. Each call to
io_rsrc_node_switch() have to be preceded with
io_rsrc_node_switch_start(). The start function is idempotent and should
not necessarily be followed by switch.
One difference is that once a node was set it will always retain a valid
rsrc node, even on unregister. It may be a nuisance at the moment, but
makes much sense for multiple types of resources. Another thing changed
is that nodes are bound to/associated with a io_rsrc_data later just
before killing (i.e. switching).
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7e9c693b4b9a2f47aa784b616ce29843021bb65a.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_rsrc_node_get() and io_rsrc_node_set() are always used together,
merge them into one so most users don't even see io_rsrc_node and don't
need to care about it.
It helped to catch io_sqe_files_register() inferring rsrc data argument
for get and set differently, not a problem but a good sign.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0827b080b2e61b3dec795380f7e1a1995595d41f.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Keep it consistent with update and use io_rsrc_node_prealloc() +
io_rsrc_node_get() in io_sqe_files_register() as well, that will be used
in future patches, not as error prone and allows to deduplicate
rsrc_node init.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cf87321e6be5e38f4dc7fe5079d2aa6945b1ace0.1617287883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Joakim reports that in some conditions he sees a multishot poll request
being canceled, and that it coincides with getting -EALREADY on
modification. As part of the poll update procedure, there's a small window
where the request is marked as canceled, and if this coincides with the
event actually triggering, then we can get a spurious -ECANCELED and
termination of the multishot request.
Don't mark the poll request as being canceled for update. We also don't
care if we race on removal unless it's a one-shot request, we can safely
updated for either case.
Fixes: b69de288e9 ("io_uring: allow events and user_data update of running poll requests")
Reported-by: Joakim Hassila <joj@mac.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that we have any worker being attached to the original task as
threads, accounting of CPU time is directly attributed to the original
task as well. This means that we no longer have to restrict SQPOLL to
needing elevated privileges, as it's really no different from just having
the task spawn a busy looping thread in userspace.
Reported-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io-wq relies on a manager thread to create/fork new workers, as needed.
But there's really no strong need for it anymore. We have the following
cases that fork a new worker:
1) Work queue. This is done from the task itself always, and it's trivial
to create a worker off that path, if needed.
2) All workers have gone to sleep, and we have more work. This is called
off the sched out path. For this case, use a task_work items to queue
a fork-worker operation.
3) Hashed work completion. Don't think we need to do anything off this
case. If need be, it could just use approach 2 as well.
Part of this change is incrementing the running worker count before the
fork, to avoid cases where we observe we need a worker and then queue
creation of one. Then new work comes in, we fork a new one. That last
queue operation should have waited for the previous worker to come up,
it's quite possible we don't even need it. Hence move the worker running
from before we fork it off to more efficiently handle that case.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This adds two new POLL_ADD flags, IORING_POLL_UPDATE_EVENTS and
IORING_POLL_UPDATE_USER_DATA. As with the other POLL_ADD flag, these are
masked into sqe->len. If set, the POLL_ADD will have the following
behavior:
- sqe->addr must contain the the user_data of the poll request that
needs to be modified. This field is otherwise invalid for a POLL_ADD
command.
- If IORING_POLL_UPDATE_EVENTS is set, sqe->poll_events must contain the
new mask for the existing poll request. There are no checks for whether
these are identical or not, if a matching poll request is found, then it
is re-armed with the new mask.
- If IORING_POLL_UPDATE_USER_DATA is set, sqe->off must contain the new
user_data for the existing poll request.
A POLL_ADD with any of these flags set may complete with any of the
following results:
1) 0, which means that we successfully found the existing poll request
specified, and performed the re-arm procedure. Any error from that
re-arm will be exposed as a completion event for that original poll
request, not for the update request.
2) -ENOENT, if no existing poll request was found with the given
user_data.
3) -EALREADY, if the existing poll request was already in the process of
being removed/canceled/completing.
4) -EACCES, if an attempt was made to modify an internal poll request
(eg not one originally issued ass IORING_OP_POLL_ADD).
The usual -EINVAL cases apply as well, if any invalid fields are set
in the sqe for this command type.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We'll need this helper for another purpose, for now just abstract it
out and have io_poll_cancel() use it for lookups.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we hit overflow and fail to allocate an overflow entry for the
completion, terminate the multishot poll mode.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The default io_uring poll mode is one-shot, where once the event triggers,
the poll command is completed and won't trigger any further events. If
we're doing repeated polling on the same file or socket, then it can be
more efficient to do multishot, where we keep triggering whenever the
event becomes true.
This deviates from the usual norm of having one CQE per SQE submitted. Add
a CQE flag, IORING_CQE_F_MORE, which tells the application to expect
further completion events from the submitted SQE. Right now the only user
of this is POLL_ADD in multishot mode.
Since sqe->poll_events is using the space that we normally use for adding
flags to commands, use sqe->len for the flag space for POLL_ADD. Multishot
mode is selected by setting IORING_POLL_ADD_MULTI in sqe->len. An
application should expect more CQEs for the specificed SQE if the CQE is
flagged with IORING_CQE_F_MORE. In multishot mode, only cancelation or an
error will terminate the poll request, in which case the flag will be
cleared.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We should be including the completion flags for better introspection on
exactly what completion event was logged.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of using a request itself for overflowed CQE stashing, allocate a
separate entry. The disadvantage is that the allocation may fail and it
will be accounted as lost (see rings->cq_overflow), so we lose reliability
in case of memory pressure if the application is driving the CQ ring into
overflow. However, it opens a way for for multiple CQEs per an SQE and
even generating SQE-less CQEs.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: use GFP_ATOMIC | __GFP_ACCOUNT]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of masking these in as part of regular POLL_ADD prep, do it in
io_init_poll_iocb(), and include NVAL as that's generally unmaskable,
and RDHUP alongside the HUP that is already set.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Expect read/write to succeed and create a hot path for this case, in
particular hide all error handling with resubmission under a single
check with the desired result.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move iov_iter_revert() resetting iterator in case of -EIOCBQUEUED into
io_resubmit_prep(), so we don't do heavy revert in hot path, also saves
a couple of checks.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When reissue_prep failed in io_complete_rw_iopoll(), we change return
code to -EIO to prevent io_iopoll_complete() from doing resubmission.
Mark requests with a new flag (i.e. REQ_F_DONT_REISSUE) instead and
retain the original return value.
It also removes io_rw_reissue() from io_iopoll_complete() that will be
used later.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
file_end_write() is only for regular files, so the function do a couple
of dereferences to get inode and check for it. However, we already have
REQ_F_ISREG at hand, just use it and inline file_end_write().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
current->files are always valid now even for io-wq threads, so kill not
used anymore REQ_F_NO_FILE_TABLE.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->work is mostly unused unless it's punted, and io_init_req() is too
hot for fully initialising it. Fortunately, we can skip init work.next
as it's controlled by io-wq, and can not touch work.flags by moving
everything related into io_prep_async_work(). The only field left is
req->work.creds, but there is nothing can be done, keep maintaining it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct io_uring_task::sqpoll is not used anymore, kill it
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_match_task() matches all requests with PF_EXITING task, even though
those may be valid requests. It was necessary for SQPOLL cancellation,
but now it kills all requests before exiting via
io_uring_cancel_sqpoll(), so it's not needed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
REQ_F_LINK_TIMEOUT is a hint that to look for linked timeouts to cancel,
we're leaving it even when it's already fired. Hence don't care to clear
it in io_kill_linked_timeout(), it's safe and is called only once.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Inline io_task_work_add() into io_req_task_work_add(). They both work
with a request, so keeping them separate doesn't make things much more
clear, but merging allows optimise it. Apart from small wins like not
reading req->ctx or not calculating @notify in the hot path, i.e. with
tctx->task_state set, it avoids doing wake_up_process() for every single
add, but only after actually done task_work_add().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_put_file() doesn't do a good job at generating a good code. Inline
it, so we can check REQ_F_FIXED_FILE first, prioritising FIXED_FILE case
over requests without files, and saving a memory load in that case.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reshuffle io_dismantle_req() checks to put most of slow path stuff under
a single if.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Inline io_clean_op(), leaving __io_clean_op() but renaming it. This will
be used in following patches.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Both io_req_complete_failed() and __io_req_task_cancel() do the same
thing: set failure flag, put both req refs and emit an CQE. The former
one is a bit more advance as it puts req back into a req cache, so make
it to take over __io_req_task_cancel() and remove the last one.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a new helper io_flush_cached_locked_reqs() that splices
locked_free_list to free_list, and does it right doing all sync and
invariant reinit.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't care about ret value in io_free_req_deferred(), make the code a
bit more concise.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
One big omission is that io_put_req() haven't been marked inline, and at
least gcc 9 doesn't inline it, not to mention that it's really hot and
extra function call is intolerable, especially when it doesn't put a
final ref.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are two problems:
1) we always allocate refnodes in advance and free them if those
haven't been used. It's expensive, takes two allocations, where one of
them is percpu. And it may be pretty common not actually using them.
2) Current API with allocating a refnode and setting some of the fields
is error prone, we don't ever want to have a file node runninng fixed
buffer callback...
Solve both with pre-init/get API. Pre-init just leaves the node for
later if not used, and for get (i.e. io_rsrc_refnode_get()), you need to
explicitly pass all arguments setting callbacks/etc., so it's more
resilient.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Emphasize that return value of io_flush_cached_reqs() depends on number
of requests in the cache. It looks nicer and might help tools from
false-negative analyses.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the case of successfully issued request by doing that check first.
It's not much of a difference, just generates slightly better code for
me.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Inline __io_queue_linked_timeout(), we don't need it
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't do a function call (io_dismantle_req()) in the middle and place it
to near other function calls, otherwise may lead to excessive register
spilling.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
First of all, w need to set tctx->sqpoll only when we add a new entry
into ->xa, so move it from the hot path. Also extract a hot path for
io_uring_add_task_file() as an inline helper.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add unlikely annotations, because my compiler pretty much mispredicts
every first check, and apart jumping around in the fast path, it also
generates extra instructions, like in advance setting ret value.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__tctx_task_work() guarantees that ctx won't be killed while running
task_works, so we can remove now unnecessary ctx pinning for internally
armed polling.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We can set canceled == true and complete out-of-line, ensure that we catch
that and correctly return -ECANCELED if the poll operation got canceled.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The correct function is io_iopoll_complete(), which deals with completions
of IOPOLL requests, not io_poll_complete().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have to dig quite deep to check for particularly whether or not a
file supports a fast-path nonblock attempt. For fixed files, we can do
this lookup once and cache the state instead.
This adds two new bits to track whether we support async read/write
attempt, and lines up the REQ_F_ISREG bit with those two. The file slot
re-uses the last 3 (or 2, for 32-bit) of the file pointer to cache that
state, and then we mask it in when we go and use a fixed file.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't allow them at registration time, so limit the check for needing
inflight tracking in io_file_get() to the non-fixed path.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use a more comprehensible() max instead of hand coding it with ifs in
io_sqd_update_thread_idle().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring manipulates references twice for each request, and hence is very
sensitive to performance of the reference count. This commit borrows a
trick from:
commit f958d7b528
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu Apr 11 10:06:20 2019 -0700
mm: make page ref count overflow check tighter and more explicit
and switches to atomic_t for references, while still retaining overflow
and underflow checks.
This is good for a 2-3% increase in peak IOPS on a single core. Before:
IOPS=2970879, IOS/call=31/31, inflight=128 (128)
IOPS=2952597, IOS/call=31/31, inflight=128 (128)
IOPS=2943904, IOS/call=31/31, inflight=128 (128)
IOPS=2930006, IOS/call=31/31, inflight=96 (96)
and after:
IOPS=3054354, IOS/call=31/31, inflight=128 (128)
IOPS=3059038, IOS/call=31/31, inflight=128 (128)
IOPS=3060320, IOS/call=31/31, inflight=128 (128)
IOPS=3068256, IOS/call=31/31, inflight=96 (96)
Signed-off-by: Jens Axboe <axboe@kernel.dk>
No functional changes in this patch, just in preparation for handling the
references a bit more efficiently.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If not for async_data NULL check, io_resubmit_prep() is already an rw
specific version of io_req_prep_async(), but slower because 1) it always
goes through io_import_iovec() even if following io_setup_async_rw() the
result 2) instead of initialising iovec/iter in-place it does it
on-stack and then copies with io_setup_async_rw().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge two function and do renaming in favour of the second one, it
relays the meaning better.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
needs_async_data controls allocation of async_data, and used in two
cases. 1) when async setup requires it (by io_req_prep_async() or
handler themselves), and 2) when op always needs additional space to
operate, like timeouts do.
Opcode preps already don't bother about the second case and do
allocation unconditionally, restrict needs_async_data to the first case
only and rename it into needs_async_setup.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: update for IOPOLL fix]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
All opcode handlers pretty well know whether they need async data or
not, and can skip testing for needs_async_data. The exception is rw
the generic path, but those test the flag by hand anyway. So, check the
flag and make io_alloc_async_data() allocating unconditionally.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_[SEND,RECV] don't need async setup neither will get into
io_req_prep_async(). Remove them from io_req_prep_async() and remove
needs_async_data checks from the related setup functions.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_cqring_fill_event() takes cflags as long to squeeze it into u32 in
an CQE, awhile all users pass int or unsigned. Replace it with unsigned
int and store it as u32 in struct io_completion to match CQE.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Always complete request holding the mutex instead of doing that strange
dancing with conditional ordering.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a simple helper doing CQE posting, marking request for link-failure,
and putting both submission and completion references.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_fixed_file_slot() and io_file_from_index() behave pretty similarly,
DRY and call one from another.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use io_req_task_queue_fail() on the fail path of io_req_task_queue().
It's unlikely to happen, so don't care about additional overhead, but
allows to keep all the req->result invariant in a single function.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't bother to take a ctx->refs for io_req_task_cancel() because it
take uring_lock before putting a request, and the context is promised to
stay alive until unlock happens.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: at fs/io_uring.c:8578 io_ring_exit_work.cold+0x0/0x18
As reissuing is now passed back by REQ_F_REISSUE and kiocb_done()
internally uses __io_complete_rw(), it may stop after setting the flag
so leaving a dangling request.
There are tricky edge cases, e.g. reading beyound file, boundary, so
the easiest way is to hand code reissue in kiocb_done() as
__io_complete_rw() was doing for us before.
Fixes: 230d50d448 ("io_uring: move reissue into regular IO path")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/f602250d292f8a84cca9a01d747744d1e797be26.1617842918.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are lots of ways r/w request may continue its path after getting
REQ_F_REISSUE, it's not necessarily io-wq and can be, e.g. apoll,
and submitted via io_async_task_func() -> __io_req_task_submit()
Clear the flag right after getting it, so the next attempt is well
prepared regardless how the request will be executed.
Fixes: 230d50d448 ("io_uring: move reissue into regular IO path")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/11dcead939343f4e27cab0074d34afcab771bfa4.1617842918.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kernel test robot correctly pinpoints a compilation failure if
CONFIG_BLOCK isn't set:
fs/io_uring.c: In function '__io_complete_rw':
>> fs/io_uring.c:2509:48: error: implicit declaration of function 'io_rw_should_reissue'; did you mean 'io_rw_reissue'? [-Werror=implicit-function-declaration]
2509 | if ((res == -EAGAIN || res == -EOPNOTSUPP) && io_rw_should_reissue(req)) {
| ^~~~~~~~~~~~~~~~~~~~
| io_rw_reissue
cc1: some warnings being treated as errors
Ensure that we have a stub declaration of io_rw_should_reissue() for
!CONFIG_BLOCK.
Fixes: 230d50d448 ("io_uring: move reissue into regular IO path")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's non-obvious how retry is done for block backed files, when it happens
off the kiocb done path. It also makes it tricky to deal with the iov_iter
handling.
Just mark the req as needing a reissue, and handling it from the
submission path instead. This makes it directly obvious that we're not
re-importing the iovec from userspace past the submit point, and it means
that we can just reuse our usual -EAGAIN retry path from the read/write
handling.
At some point in the future, we'll gain the ability to always reliably
return -EAGAIN through the stack. A previous attempt on the block side
didn't pan out and got reverted, hence the need to check for this
information out-of-band right now.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
iov_iter_revert() is done in completion handlers that happensf before
read/write returns -EIOCBQUEUED, no need to repeat reverting afterwards.
Moreover, even though it may appear being just a no-op, it's actually
races with 1) user forging a new iovec of a different size 2) reissue,
that is done via io-wq continues completely asynchronously.
Fixes: 3e6a0d3c75 ("io_uring: fix -EAGAIN retry with IOPOLL")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
task_pid may be large enough to not fit into the left space of
TASK_COMM_LEN-sized buffers and overflow in sprintf. We not so care
about uniqueness, so replace it with safer snprintf().
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1702c6145d7e1c46fbc382f28334c02e1a3d3994.1617267273.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
S_ISBLK is marked as unbounded work for async preparation, because it
doesn't match S_ISREG. That is incorrect, as any read/write to a block
device is also a bounded operation. Fix it up and ensure that S_ISBLK
isn't marked unbounded.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't call into get_signal() with the sqd mutex held, it'll fail if we're
freezing the task and we'll get complaints on locks still being held:
====================================
WARNING: iou-sqp-8386/8387 still has locks held!
5.12.0-rc4-syzkaller #0 Not tainted
------------------------------------
1 lock held by iou-sqp-8386/8387:
#0: ffff88801e1d2470 (&sqd->lock){+.+.}-{3:3}, at: io_sq_thread+0x24c/0x13a0 fs/io_uring.c:6731
stack backtrace:
CPU: 1 PID: 8387 Comm: iou-sqp-8386 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120
try_to_freeze include/linux/freezer.h:66 [inline]
get_signal+0x171a/0x2150 kernel/signal.c:2576
io_sq_thread+0x8d2/0x13a0 fs/io_uring.c:6748
Fold the get_signal() case in with the parking checks, as we need to drop
the lock in both cases, and since we need to be checking for parking when
juggling the lock anyway.
Reported-by: syzbot+796d767eb376810256f5@syzkaller.appspotmail.com
Fixes: dbe1bdbb39 ("io_uring: handle signals for IO threads like a normal thread")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
general protection fault, probably for non-canonical address
0xdffffc0000000018: 0000 [#1] KASAN: null-ptr-deref
in range [0x00000000000000c0-0x00000000000000c7]
RIP: 0010:io_commit_cqring+0x37f/0xc10 fs/io_uring.c:1318
Call Trace:
io_kill_timeouts+0x2b5/0x320 fs/io_uring.c:8606
io_ring_ctx_wait_and_kill+0x1da/0x400 fs/io_uring.c:8629
io_uring_create fs/io_uring.c:9572 [inline]
io_uring_setup+0x10da/0x2ae0 fs/io_uring.c:9599
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
It can get into wait_and_kill() before setting up ctx->rings, and hence
io_commit_cqring() fails. Mimic poll cancel and do it only when we
completed events, there can't be any requests if it failed before
initialising rings.
Fixes: 80c4cbdb5e ("io_uring: do post-completion chore on t-out cancel")
Reported-by: syzbot+0e905eb8228070c457a0@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/660261a48f0e7abf260c8e43c87edab3c16736fa.1617014345.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Always try to do cancellation in __io_uring_task_cancel() at least once,
so it actually goes and cleans its sqpoll tasks (i.e. via
io_sqpoll_cancel_sync()), otherwise sqpoll task may submit new requests
after cancellation and it's racy for many reasons.
Fixes: 521d6a737a ("io_uring: cancel sqpoll via task_work")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0a21bd6d794bb1629bc906dd57a57b2c2985a8ac.1616839147.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is an assignment to io that is never read after the assignment,
the assignment is redundant and can be removed.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As tasks always wait and kill their io-wq on exec/exit, files are of no
more concern to us, so we don't need to specifically cancel them by hand
in those cases. Moreover we should not, because io_match_task() looks at
req->task->files now, which is always true and so leads to extra
cancellations, that wasn't a case before per-task io-wq.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0566c1de9b9dd417f5de345c817ca953580e0e2e.1616696997.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't forget about io_commit_cqring() + io_cqring_ev_posted() after
exit/exec cancelling timeouts. Both functions declared only after
io_kill_timeouts(), so to avoid tons of forward declarations move
it down.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/72ace588772c0f14834a6a4185d56c445a366fb4.1616696997.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We go through various hoops to disallow signals for the IO threads, but
there's really no reason why we cannot just allow them. The IO threads
never return to userspace like a normal thread, and hence don't go through
normal signal processing. Instead, just check for a pending signal as part
of the work loop, and call get_signal() to handle it for us if anything
is pending.
With that, we can support receiving signals, including special ones like
SIGSTOP.
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Arguably we want CQEs of linked requests be in a strict order of
submission as it always was. Now if init of a request fails its CQE may
be posted before all prior linked requests including the head of the
link. Fix it by failing it last.
Fixes: de59bc104c ("io_uring: fail links more in io_submit_sqe()")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b7a96b05832e7ab23ad55f84092a2548c4a888b0.1616699075.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: CPU: 1 PID: 27907 at fs/io_uring.c:7147 io_sq_thread_park+0xb5/0xd0 fs/io_uring.c:7147
CPU: 1 PID: 27907 Comm: iou-sqp-27905 Not tainted 5.12.0-rc4-syzkaller #0
RIP: 0010:io_sq_thread_park+0xb5/0xd0 fs/io_uring.c:7147
Call Trace:
io_ring_ctx_wait_and_kill+0x214/0x700 fs/io_uring.c:8619
io_uring_release+0x3e/0x50 fs/io_uring.c:8646
__fput+0x288/0x920 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:140
io_run_task_work fs/io_uring.c:2238 [inline]
io_run_task_work fs/io_uring.c:2228 [inline]
io_uring_try_cancel_requests+0x8ec/0xc60 fs/io_uring.c:8770
io_uring_cancel_sqpoll+0x1cf/0x290 fs/io_uring.c:8974
io_sqpoll_cancel_cb+0x87/0xb0 fs/io_uring.c:8907
io_run_task_work_head+0x58/0xb0 fs/io_uring.c:1961
io_sq_thread+0x3e2/0x18d0 fs/io_uring.c:6763
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
May happen that last ctx ref is killed in io_uring_cancel_sqpoll(), so
fput callback (i.e. io_uring_release()) is enqueued through task_work,
and run by same cancellation. As it's deeply nested we can't do parking
or taking sqd->lock there, because its state is unclear. So avoid
ctx ejection from sqd list from io_ring_ctx_wait_and_kill() and do it
in a clear context in io_ring_exit_work().
Fixes: f6d54255f4 ("io_uring: halt SQO submission on ctx exit")
Reported-by: syzbot+e3a3f84f5cecf61f0583@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e90df88b8ff2cabb14a7534601d35d62ab4cb8c7.1616496707.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_provide_buffers_prep()'s "p->len * p->nbufs" to sign extension
problems. Not a huge problem as it's only used for access_ok() and
increases the checked length, but better to keep typing right.
Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: efe68c1ca8 ("io_uring: validate the full range of provided buffers for access")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/562376a39509e260d8532186a06226e56eb1f594.1616149233.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linus correctly points out that this is both unnecessary and generates
much worse code on some archs as going from current to thread_info is
actually backwards - and obviously just wasteful, since the thread_info
is what we care about.
Since io_uring only operates on current for these operations, just use
test_thread_flag() instead. For io-wq, we can further simplify and use
tracehook_notify_signal() to handle the TIF_NOTIFY_SIGNAL work and clear
the flag. The latter isn't an actual bug right now, but it may very well
be in the future if we place other work items under TIF_NOTIFY_SIGNAL.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/io-uring/CAHk-=wgYhNck33YHKZ14mFB5MzTTk8gqXHcfj=RWTAXKwgQJgg@mail.gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Without that it's not safe to use them in a linked combination with
others.
Now combinations like IORING_OP_SENDMSG followed by IORING_OP_SPLICE
should be possible.
We already handle short reads and writes for the following opcodes:
- IORING_OP_READV
- IORING_OP_READ_FIXED
- IORING_OP_READ
- IORING_OP_WRITEV
- IORING_OP_WRITE_FIXED
- IORING_OP_WRITE
- IORING_OP_SPLICE
- IORING_OP_TEE
Now we have it for these as well:
- IORING_OP_SENDMSG
- IORING_OP_SEND
- IORING_OP_RECVMSG
- IORING_OP_RECV
For IORING_OP_RECVMSG we also check for the MSG_TRUNC and MSG_CTRUNC
flags in order to call req_set_fail_links().
There might be applications arround depending on the behavior
that even short send[msg]()/recv[msg]() retuns continue an
IOSQE_IO_LINK chain.
It's very unlikely that such applications pass in MSG_WAITALL,
which is only defined in 'man 2 recvmsg', but not in 'man 2 sendmsg'.
It's expected that the low level sock_sendmsg() call just ignores
MSG_WAITALL, as MSG_ZEROCOPY is also ignored without explicitly set
SO_ZEROCOPY.
We also expect the caller to know about the implicit truncation to
MAX_RW_COUNT, which we don't detect.
cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/c4e1a4cc0d905314f4d5dc567e65a7b09621aab3.1615908477.git.metze@samba.org
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Attaching to already dead/dying SQPOLL task is disallowed in
io_sq_offload_create(), but cleanup is hand coded by calling
io_put_sq_data()/etc., that miss to put ctx->sq_creds.
Defer everything to error-path io_sq_thread_finish(), adding
ctx->sqd_list in the error case as well as finish will handle it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Running sqpoll cancellations via task_work_run() is a bad idea because
it depends on other task works to be run, but those may be locked in
currently running task_work_run() because of how it's (splicing the list
in batches).
Enqueue and run them through a separate callback head, namely
struct io_sq_data::park_task_work. As a nice bonus we now precisely
control where it's run, that's much safer than guessing where it can
happen as it was before.
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We already have helpers to run/add callback_head but taking ctx and
working with ctx->exit_task_work. Extract generic versions of them
implemented in terms of struct callback_head, it will be used later.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If io_sq_thread_park() of one task got rescheduled right after
set_bit(), before it gets back to mutex_lock() there can happen
park()/unpark() by another task with SQPOLL locking again and
continuing running never seeing that first set_bit(SHOULD_PARK),
so won't even try to put the mutex down for parking.
It will get parked eventually when SQPOLL drops the lock for reschedule,
but may be problematic and will get in the way of further fixes.
Account number of tasks waiting for parking with a new atomic variable
park_pending and adjust SHOULD_PARK accordingly. It doesn't entirely
replaces SHOULD_PARK bit with this atomic var because it's convenient
to have it as a bit in the state and will help to do optimisations
later.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_sq_thread_finish() is called in io_ring_ctx_free(), so SQPOLL task is
potentially running submitting new requests. It's not a disaster because
of using a "try" variant of percpu_ref_get, but is far from nice.
Remove ctx from the sqd ctx list earlier, before cancellation loop, so
SQPOLL can't find it and so won't submit new requests.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The only user of read-locking of sqd->rw_lock is sq_thread itself, which
is by definition alone, so we don't really need rw_semaphore, but mutex
will do. Replace it with a mutex, and kill read-to-write upgrading and
extra task_work handling in io_sq_thread().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If io_req_complete_post() put not a final ref, we can't rely on the
request's ctx ref, and so ctx may potentially be freed while
complete_post() is in io_cqring_ev_posted()/etc.
In that case get an additional ctx reference, and put it in the end, so
protecting following io_cqring_ev_posted(). And also prolong ctx
lifetime until spin_unlock happens, as we do with mutexes, so added
percpu_ref_get() doesn't race with ctx free.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's racy to modify req->flags from a not owning context, e.g. linked
timeout calling req_set_fail_links() for the master request might race
with that request setting/clearing flags while being executed
concurrently. Just remove req_set_fail_links(prev) from
io_link_timeout_fn(), io_async_find_and_cancel() and functions down the
line take care of setting the fail bit.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Like we did for the personality idr, convert the IO buffer idr to use
XArray. This avoids a use-after-free on removal of entries, since idr
doesn't like doing so from inside an iterator, and it nicely reduces
the amount of code we need to support this feature.
Fixes: 5a2e745d4d ("io_uring: buffer registration infrastructure")
Cc: stable@vger.kernel.org
Cc: Matthew Wilcox <willy@infradead.org>
Cc: yangerkun <yangerkun@huawei.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the freezer using the proper signaling to notify us of when it's
time to freeze a thread, we can re-enable normal freezer usage for the
IO threads. Ensure that SQPOLL, io-wq, and the io-wq manager call
try_to_freeze() appropriately, and remove the default setting of
PF_NOFREEZE from create_io_thread().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_ASYNC_CANCEL tries io-wq cancellation only for current task.
If it fails go over tctx_list and try it out for every single tctx.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1) The first problem is io_uring_cancel_sqpoll() ->
io_uring_cancel_task_requests() basically doing park(); park(); and so
hanging.
2) Another one is more subtle, when the master task is doing cancellations,
but SQPOLL task submits in-between the end of the cancellation but
before finish() requests taking a ref to the ctx, and so eternally
locking it up.
3) Yet another is a dying SQPOLL task doing io_uring_cancel_sqpoll() and
same io_uring_cancel_sqpoll() from the owner task, they race for
tctx->wait events. And there probably more of them.
Instead do SQPOLL cancellations from within SQPOLL task context via
task_work, see io_sqpoll_cancel_sync(). With that we don't need temporal
park()/unpark() during cancellation, which is ugly, subtle and anyway
doesn't allow to do io_run_task_work() properly.
io_uring_cancel_sqpoll() is called only from SQPOLL task context and
under sqd locking, so all parking is removed from there. And so,
io_sq_thread_[un]park() and io_sq_thread_stop() are not used now by
SQPOLL task, and that spare us from some headache.
Also remove ctx->sqd_list early to avoid 2). And kill tctx->sqpoll,
which is not used anymore.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
SQPOLL thread to which we're trying to attach may be going away, it's
not nice but a more serious problem is if io_sq_offload_create() sees
sqd->thread==NULL, and tries to init it with a new thread. There are
tons of ways it can be exploited or fail.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We always do complete(&sqd->startup) almost right after sqd->thread
creation, either in the success path or in io_sq_thread_finish(). It's
specifically created not started for us to be able to set some stuff
like sqd->thread and io_uring_alloc_task_context() before following
right after wake_up_new_task().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As io_uring_cancel_files() and others let SQO to run between
io_uring_try_cancel_requests(), SQO may generate new deferred requests,
so it's safer to try to cancel them in it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We bypass IOPOLL completion polling (and reaping) for the SQPOLL thread,
but if it's the thread itself invoking cancelations, then we still need
to perform it or no one will.
Fixes: 9936c7c2bc ("io_uring: deduplicate core cancellations sequence")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Earlier kernels had SQPOLL threads that could share across anything, as
we grabbed the context we needed on a per-ring basis. This is no longer
the case, so only allow attaching directly if we're in the same thread
group. That is the common use case. For non-group tasks, just setup a
new context and thread as we would've done if sharing wasn't set. This
isn't 100% ideal in terms of CPU utilization for the forked and share
case, but hopefully that isn't much of a concern. If it is, there are
plans in motion for how to improve that. Most importantly, we want to
avoid app side regressions where sharing worked before and now doesn't.
With this patch, functionality is equivalent to previous kernels that
supported IORING_SETUP_ATTACH_WQ with SQPOLL.
Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We use ->ctx_new_list to notify sqo about new ctx pending, then sqo
should stop and splice it to its sqd->ctx_list, paired with
->sq_thread_comp.
The last one is broken because nobody reinitialises it, and trying to
fix it would only add more complexity and bugs. And the first isn't
really needed as is done under park(), that protects from races well.
Add ctx into sqd->ctx_list directly (under park()), it's much simpler
and allows to kill both, ctx_new_list and sq_thread_comp.
note: apparently there is no real problem at the moment, because
sq_thread_comp is used only by io_sq_thread_finish() followed by
parking, where list_del(&ctx->sqd_list) removes it well regardless
whether it's in the new or the active list.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have to set ctx->sq_thread_idle before adding a ring to an SQ task,
otherwise sqd races for seeing zero and accounting it as such.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The io-wq threads were already marked as no-freeze, but the manager was
not. On resume, we perpetually have signal_pending() being true, and
hence the manager will loop and spin 100% of the time.
Just mark the tasks created by create_io_thread() as PF_NOFREEZE by
default, and remove any knowledge of it in io-wq and io_uring.
Reported-by: Kevin Locke <kevin@kevinlocke.name>
Tested-by: Kevin Locke <kevin@kevinlocke.name>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have a tiny race where io_put_sq_data() calls io_sq_thead_stop()
and finds the thread gone, but the thread has indeed not fully
exited or called complete() yet. Close it up by always having
io_sq_thread_stop() wait on completion of the exit event.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix the following coccicheck warning:
./fs/io_uring.c:8984:5-8: Unneeded variable: "ret". Return "0" on line
8998
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/1615271441-33649-1-git-send-email-yang.lee@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we hit an error path in the function, make sure that the io_kiocb is
fully initialized at that point so that freeing the request always sees
a valid state.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Calling io_queue_next() after spin_unlock in io_req_complete_post()
races with the other side extracting and reusing this request. Hand
coded parts of io_req_find_next() considering that io_disarm_next()
and io_req_task_queue() have (and safe) to be called with
completion_lock held.
It already does io_commit_cqring() and io_cqring_ev_posted(), so just
reuse it for post io_disarm_next().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5672a62f3150ee7c55849f40c0037655c4f2840f.1615250156.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A preparation patch placing all preparations before extracting a next
request into a separate helper io_disarm_next().
Also, don't spuriously do ev_posted in a rare case where REQ_F_FAIL_LINK
is set but there are no requests linked (i.e. after cancelling a linked
timeout or setting IOSQE_IO_LINK on a last request of a submission
batch).
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/44ecff68d6b47e1c4e6b891bdde1ddc08cfc3590.1615250156.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't set IO_SQ_THREAD_SHOULD_STOP when io_sq_offload_create() has
failed on io_uring_alloc_task_context() but leave everything to
io_sq_thread_finish(), because currently io_sq_thread_finish()
hangs on trying to park it. That's great it stalls there, because
otherwise the following io_sq_thread_stop() would be skipped on
IO_SQ_THREAD_SHOULD_STOP check and the sqo would race for sqd with
freeing ctx.
A simple error injection gives something like this.
[ 245.463955] INFO: task sqpoll-test-hang:523 blocked for more than 122 seconds.
[ 245.463983] Call Trace:
[ 245.463990] __schedule+0x36b/0x950
[ 245.464005] schedule+0x68/0xe0
[ 245.464013] schedule_timeout+0x209/0x2a0
[ 245.464032] wait_for_completion+0x8b/0xf0
[ 245.464043] io_sq_thread_finish+0x44/0x1a0
[ 245.464049] io_uring_setup+0x9ea/0xc80
[ 245.464058] __x64_sys_io_uring_setup+0x16/0x20
[ 245.464064] do_syscall_64+0x38/0x50
[ 245.464073] entry_SYSCALL_64_after_hwframe+0x44/0xae
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
You can't call idr_remove() from within a idr_for_each() callback,
but you can call xa_erase() from an xa_for_each() loop, so switch the
entire personality_idr from the IDR to the XArray. This manifests as a
use-after-free as idr_for_each() attempts to walk the rest of the node
after removing the last entry from it.
Fixes: 071698e13a ("io_uring: allow registering credentials")
Cc: stable@vger.kernel.org # 5.6+
Reported-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
[Pavel: rebased (creds load was moved into io_init_req())]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/7ccff36e1375f2b0ebf73d957f037b43becc0dde.1615212806.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are enough of problems with IORING_SETUP_R_DISABLED, including the
burden of checking and kicking off the SQO task all over the codebase --
for exit/cancel/etc.
Rework it, always start the thread but don't do submit unless the flag
is gone, that's much easier.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io-wq now is per-task, so cancellations now should match against
request's ctx.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We keep running into weird dependency issues between the sqd lock and
the parking state. Disentangle the SQPOLL thread from the last bits of
the kthread parking inheritance, and just replace the parking state,
and two associated locks, with a single rw mutex. The SQPOLL thread
keeps the mutex for read all the time, except if someone has marked us
needing to park. Then we drop/re-acquire and try again.
This greatly simplifies the parking state machine (by just getting rid
of it), and makes it a lot more obvious how it works - if you need to
modify the ctx list, then you simply park the thread which will grab
the lock for writing.
Fold in fix from Hillf Danton on not setting STOP on a fatal signal.
Fixes: e54945ae94 ("io_uring: SQPOLL stop error handling fixes")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This brings the behavior back in line with what 5.11 and earlier did,
and this is no longer needed with the improved handling of creds
not needing to do unshare().
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With IORING_SETUP_ATTACH_WQ we should let __io_sq_thread() use the
initial creds from each ctx.
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_ring_exit_work() have to cancel all requests, including those staying
in io-wq, however it tries only cancellation of current tctx, which is
NULL. If we've got task==NULL, use the ctx-to-tctx map to go over all
tctx/io-wq and try cancellations on them.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We use system_unbound_wq to run io_ring_exit_work(), so it's hard to
monitor whether removal hang or not. Add WARN_ONCE to catch hangs.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't use task file notes anymore, and no need left in indexing
task->io_uring->xa by file, and replace it with ctx. It's better
design-wise, especially since we keep a dangling file, and so have to
keep an eye on not dereferencing it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With ->flush() gone we're now leaving all uring file notes until the
task dies/execs, so the ctx will not be freed until all tasks that have
ever submit a request die. It was nicer with flush but not much, we
could have locked as described ctx in many cases.
Now we guarantee that ctx outlives all tctx in a sense that
io_ring_exit_work() waits for all tctxs to drop their corresponding
enties in ->xa, and ctx won't go away until then. Hence, additional
io_uring file reference (a.k.a. task file notes) are not needed anymore.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Another preparation patch. When full quiesce is done on ctx exit, use
task_work infra to remove corresponding to the ctx io_uring->xa entries.
For that we use the back tctx map. Also use ->in_idle to prevent
removing it while we traversing ->xa on cancellation, just ignore it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For each pair tcxt-ctx create an object and chain it into ctx, so we
have a way to traverse all tctx that are using current ctx. Preparation
patch, will be used later.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rework io_uring_del_task_file(), so it accepts an index to delete, and
it's not necessarily have to be in the ->xa. Infer file from xa_erase()
to maintain a single origin of truth.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we go async with a request, grab the creds that the task currently has
assigned and make sure that the async side switches to them. This is
handled in the same way that we do for registered personalities.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
45d189c606 ("io_uring: replace force_nonblock with flags") did
something strange for io_openat() slicing all issue_flags but
IO_URING_F_NONBLOCK. Not a bug for now, but better to just forward the
flags.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have this weird true/false return from parking, and then some of the
callers decide to look at that. It can lead to unbalanced parks and
sqd locking. Have the callers check the thread status once it's parked.
We know we have the lock at that point, so it's either valid or it's NULL.
Fix race with parking on thread exit. We need to be careful here with
ordering of the sdq->lock and the IO_SQ_THREAD_SHOULD_PARK bit.
Rename sqd->completion to sqd->parked to reflect that this is the only
thing this completion event doesn.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The callback can only be armed, if we get -EIOCBQUEUED returned. It's
important that we clear the WAITQ bit for other cases, otherwise we can
queue for async retry and filemap will assume that we're armed and
return -EAGAIN instead of just blocking for the IO.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It doesn't make sense to wait for more events to come in, if we can't
even flush the overflow we already have to the ring. Return -EBUSY for
that condition, just like we do for attempts to submit with overflow
pending.
Cc: stable@vger.kernel.org # 5.11
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This allows us to do task creation and setup without needing to use
completions to try and synchronize with the starting thread. Get rid of
the old io_wq_fork_thread() wrapper, and the 'wq' and 'worker' startup
completion events - we can now do setup before the task is running.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linked timeouts are fired asynchronously (i.e. soft-irq), and use
generic cancellation paths to do its stuff, including poking into io-wq.
The problem is that it's racy to access tctx->io_wq, as
io_uring_task_cancel() and others may be happening at this exact moment.
Mark linked timeouts with REQ_F_INLIFGHT for now, making sure there are
no timeouts before io-wq destraction.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of going into request internals, like checking req->file->f_op,
do match them based on REQ_F_INFLIGHT, it's set only when we want it to
be reliably cancelled.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_dismantle_req() is always followed by io_put_task(), which already do
proper in_idle wake ups, so we can skip waking the owner task in
io_dismantle_req(). The rules are simpler now, do io_put_task() shortly
after ending a request, and it will be fine.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_queue_async_work() is only called from io_queue_async_work(),
inline it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Inline io_req_clean_work(), less code and easier to analyse
tctx dependencies and refs usage.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When we cancel SQPOLL, @task in io_uring_try_cancel_requests() will
differ from current. Use the right tctx from passed in @task, and don't
forget that it can be NULL when the io_uring ctx exits.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We no longer revert the iovec on -EIOCBQUEUED, see commit ab2125df92,
and this started causing issues for IOPOLL on devies that run out of
request slots. Turns out what outside of needing a revert for those, we
also had a bug where we didn't properly setup retry inside the submission
path. That could cause re-import of the iovec, if any, and that could lead
to spurious results if the application had those allocated on the stack.
Catch -EAGAIN retry and make the iovec stable for IOPOLL, just like we do
for !IOPOLL retries.
Cc: <stable@vger.kernel.org> # 5.9+
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Reported-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now, sqo_task is used only for a warning that is not interesting anymore
since sqo_dead is gone, remove all of that including ctx->sqo_task.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As SQPOLL task doesn't poke into ->sqo_task anymore, there is no need to
kill the sqo when the master task exits. Before it was necessary to
avoid races accessing sqo_task->files with removing them.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: don't forget to enable SQPOLL before exit, if started disabled]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we create it in a disabled state because IORING_SETUP_R_DISABLED is
set on ring creation, we need to ensure that we've kicked the thread if
we're exiting before it's been explicitly disabled. Otherwise we can run
into a deadlock where exit is waiting go park the SQPOLL thread, but the
SQPOLL thread itself is waiting to get a signal to start.
That results in the below trace of both tasks hung, waiting on each other:
INFO: task syz-executor458:8401 blocked for more than 143 seconds.
Not tainted 5.11.0-next-20210226-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor458 state:D stack:27536 pid: 8401 ppid: 8400 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4324 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5075
schedule+0xcf/0x270 kernel/sched/core.c:5154
schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x168/0x270 kernel/sched/completion.c:138
io_sq_thread_park fs/io_uring.c:7115 [inline]
io_sq_thread_park+0xd5/0x130 fs/io_uring.c:7103
io_uring_cancel_task_requests+0x24c/0xd90 fs/io_uring.c:8745
__io_uring_files_cancel+0x110/0x230 fs/io_uring.c:8840
io_uring_files_cancel include/linux/io_uring.h:47 [inline]
do_exit+0x299/0x2a60 kernel/exit.c:780
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43e899
RSP: 002b:00007ffe89376d48 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00000000004af2f0 RCX: 000000000043e899
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 0000000010000000
R10: 0000000000008011 R11: 0000000000000246 R12: 00000000004af2f0
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
INFO: task iou-sqp-8401:8402 can't die for more than 143 seconds.
task:iou-sqp-8401 state:D stack:30272 pid: 8402 ppid: 8400 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4324 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5075
schedule+0xcf/0x270 kernel/sched/core.c:5154
schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x168/0x270 kernel/sched/completion.c:138
io_sq_thread+0x27d/0x1ae0 fs/io_uring.c:6717
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
INFO: task iou-sqp-8401:8402 blocked for more than 143 seconds.
Reported-by: syzbot+fb5458330b4442f2090d@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_run_ctx_fallback() can use xchg() instead of cmpxchg(). It's simpler
and faster.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is an unlikely but possible race using a freed context. That's
because req->task_work.func() can free a request, but we won't
necessarily find a completion in submit_state.comp and so all ctx refs
may be put by the time we do mutex_lock(&ctx->uring_ctx);
There are several reasons why it can miss going through
submit_state.comp: 1) req->task_work.func() didn't complete it itself,
but punted to iowq (e.g. reissue) and it got freed later, or a similar
situation with it overflowing and getting flushed by someone else, or
being submitted to IRQ completion, 2) As we don't hold the uring_lock,
someone else can do io_submit_flush_completions() and put our ref.
3) Bugs and code obscurities, e.g. failing to propagate issue_flags
properly.
One example is as follows
CPU1 | CPU2
=======================================================================
@req->task_work.func() |
-> @req overflwed, |
so submit_state.comp,nr==0 |
| flush overflows, and free @req
| ctx refs == 0, free it
ctx is dead, but we do |
lock + flush + unlock |
So take a ctx reference for each new ctx we see in __tctx_task_work(),
and do release it until we do all our flushing.
Fixes: 65453d1efb ("io_uring: enable req cache for task_work items")
Reported-by: syzbot+a157ac7c03a56397f553@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: fold in my one-liner and fix ref mismatch]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We already run the fallback task_work in io_uring_try_cancel_requests(),
no need to duplicate at ring exit explicitly.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we move it in there, then we no longer have to care about it in io-wq.
This means we can drop the cred handling in io-wq, and we can drop the
REQ_F_WORK_INITIALIZED flag and async init functions as that was the last
user of it since we moved to the new workers. Then we can also drop
io_wq_work->creds, and just hold the personality u16 in there instead.
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We're no longer checking anything that requires the work item to be
initialized, as we're not carrying any file related state there.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Destroy current's io-wq backend and tctx on __io_uring_task_cancel(),
aka exec(). Looks it's not strictly necessary, because it will be done
at some point when the task dies and changes of creds/files/etc. are
handled, but better to do that earlier to free io-wq and not potentially
lock previous mm and other resources for the time being.
It's safe to do because we wait for all requests of the current task to
complete, so no request will use tctx afterwards. Note, that
io_uring_files_cancel() may leave some requests for later reaping, so it
leaves tctx intact, that's ok as the task is dying anyway.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make sure that we killed an io-wq by the time a task is dead.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We clear the bit marking the ctx task_work as active after having run
the queued work, but we really should be clearing it before. Otherwise
we can hit a tiny race ala:
CPU0 CPU1
io_task_work_add() tctx_task_work()
run_work
add_to_list
test_and_set_bit
clear_bit
already set
and CPU0 will return thinking the task_work is queued, while in reality
it's already being run. If we hit the condition after __tctx_task_work()
found no more work, but before we've cleared the bit, then we'll end up
thinking it's queued and will be run. In reality it is queued, but we
didn't queue the ctx task_work to ensure that it gets run.
Fixes: 7cbf1722d5 ("io_uring: provide FIFO ordering for task_work")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we put the io-wq from io_uring, we really want it to exit. Provide
a helper that does that for us. Couple that with not having the manager
hold a reference to the 'wq' and the normal SQPOLL exit will tear down
the io-wq context appropriate.
On the io-wq side, our wq context is per task, so only the task itself
is manipulating ->manager and hence it's safe to check and clear without
any extra locking. We just need to ensure that the manager task stays
around, in case it exits.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We want to reuse this completion, and a single complete should do just
fine. Ensure that we park ourselves first if requested, as that is what
lead to the initial deadlock in this area. If we've got someone attempting
to park us, then we can't proceed without having them finish first.
Fixes: 37d1e2e364 ("io_uring: move SQPOLL thread io-wq forked worker")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring_try_cancel_requests() matches not only current's requests, but
also of other exiting tasks, so we need to actively cancel them and not
just wait, especially since the function can be called on flush during
do_exit() -> exit_files().
Even if it's not a problem for now, it's much nicer to know that the
function tries to cancel everything it can.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we fail to fork an SQPOLL worker, we can hit cancel, and hence
attempted thread stop, with the thread already being stopped. Ensure
we check for that.
Also guard thread stop fully by the sqd mutex, just like we do for
park.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block
Pull io_uring thread rewrite from Jens Axboe:
"This converts the io-wq workers to be forked off the tasks in question
instead of being kernel threads that assume various bits of the
original task identity.
This kills > 400 lines of code from io_uring/io-wq, and it's the worst
part of the code. We've had several bugs in this area, and the worry
is always that we could be missing some pieces for file types doing
unusual things (recent /dev/tty example comes to mind, userfaultfd
reads installing file descriptors is another fun one... - both of
which need special handling, and I bet it's not the last weird oddity
we'll find).
With these identical workers, we can have full confidence that we're
never missing anything. That, in itself, is a huge win. Outside of
that, it's also more efficient since we're not wasting space and code
on tracking state, or switching between different states.
I'm sure we're going to find little things to patch up after this
series, but testing has been pretty thorough, from the usual
regression suite to production. Any issue that may crop up should be
manageable.
There's also a nice series of further reductions we can do on top of
this, but I wanted to get the meat of it out sooner rather than later.
The general worry here isn't that it's fundamentally broken. Most of
the little issues we've found over the last week have been related to
just changes in how thread startup/exit is done, since that's the main
difference between using kthreads and these kinds of threads. In fact,
if all goes according to plan, I want to get this into the 5.10 and
5.11 stable branches as well.
That said, the changes outside of io_uring/io-wq are:
- arch setup, simple one-liner to each arch copy_thread()
implementation.
- Removal of net and proc restrictions for io_uring, they are no
longer needed or useful"
* tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block: (30 commits)
io-wq: remove now unused IO_WQ_BIT_ERROR
io_uring: fix SQPOLL thread handling over exec
io-wq: improve manager/worker handling over exec
io_uring: ensure SQPOLL startup is triggered before error shutdown
io-wq: make buffered file write hashed work map per-ctx
io-wq: fix race around io_worker grabbing
io-wq: fix races around manager/worker creation and task exit
io_uring: ensure io-wq context is always destroyed for tasks
arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread()
io_uring: cleanup ->user usage
io-wq: remove nr_process accounting
io_uring: flag new native workers with IORING_FEAT_NATIVE_WORKERS
net: remove cmsg restriction from io_uring based send/recvmsg calls
Revert "proc: don't allow async path resolution of /proc/self components"
Revert "proc: don't allow async path resolution of /proc/thread-self components"
io_uring: move SQPOLL thread io-wq forked worker
io-wq: make io_wq_fork_thread() available to other users
io-wq: only remove worker from free_list, if it was there
io_uring: remove io_identity
io_uring: remove any grabbing of context
...
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Merge tag 'for-5.12/io_uring-2021-02-25' of git://git.kernel.dk/linux-block
Pull more io_uring updates from Jens Axboe:
"A collection of later fixes that we should get into this release:
- Series of submission cleanups (Pavel)
- A few fixes for issues from earlier this merge window (Pavel, me)
- IOPOLL resubmission fix
- task_work locking fix (Hao)"
* tag 'for-5.12/io_uring-2021-02-25' of git://git.kernel.dk/linux-block: (25 commits)
Revert "io_uring: wait potential ->release() on resurrect"
io_uring: fix locked_free_list caches_free()
io_uring: don't attempt IO reissue from the ring exit path
io_uring: clear request count when freeing caches
io_uring: run task_work on io_uring_register()
io_uring: fix leaving invalid req->flags
io_uring: wait potential ->release() on resurrect
io_uring: keep generic rsrc infra generic
io_uring: zero ref_node after killing it
io_uring: make the !CONFIG_NET helpers a bit more robust
io_uring: don't hold uring_lock when calling io_run_task_work*
io_uring: fail io-wq submission from a task_work
io_uring: don't take uring_lock during iowq cancel
io_uring: fail links more in io_submit_sqe()
io_uring: don't do async setup for links' heads
io_uring: do io_*_prep() early in io_submit_sqe()
io_uring: split sqe-prep and async setup
io_uring: don't submit link on error
io_uring: move req link into submit_state
io_uring: move io_init_req() into io_submit_sqe()
...
Just like the changes for io-wq, ensure that we re-fork the SQPOLL
thread if the owner execs. Mark the ctx sq thread as sqo_exec if
it dies, and the ring as needing a wakeup which will force the task
to enter the kernel. When it does, setup the new thread and proceed
as usual.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
exec will cancel any threads, including the ones that io-wq is using. This
isn't a problem, in fact we'd prefer it to be that way since it means we
know that any async work cancels naturally without having to handle it
proactively.
But it does mean that we need to setup a new manager, as the manager and
workers are gone. Handle this at queue time, and cancel work if we fail.
Since the manager can go away without us noticing, ensure that the manager
itself holds a reference to the 'wq' as well. Rename io_wq_destroy() to
io_wq_put() to reflect that.
In the future we can now simplify exec cancelation handling, for now just
leave it the same.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
syzbot reports the following hang:
INFO: task syz-executor.0:12538 can't die for more than 143 seconds.
task:syz-executor.0 state:D stack:28352 pid:12538 ppid: 8423 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4324 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5075
schedule+0xcf/0x270 kernel/sched/core.c:5154
schedule_timeout+0x1db/0x250 kernel/time/timer.c:1868
do_wait_for_common kernel/sched/completion.c:85 [inline]
__wait_for_common kernel/sched/completion.c:106 [inline]
wait_for_common kernel/sched/completion.c:117 [inline]
wait_for_completion+0x168/0x270 kernel/sched/completion.c:138
io_sq_thread_finish+0x96/0x580 fs/io_uring.c:7152
io_sq_offload_create fs/io_uring.c:7929 [inline]
io_uring_create fs/io_uring.c:9465 [inline]
io_uring_setup+0x1fb2/0x2c20 fs/io_uring.c:9550
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xae
which is due to exiting after the SQPOLL thread has been created, but
hasn't been started yet. Ensure that we always complete the startup
side when waiting for it to exit.
Reported-by: syzbot+c927c937cba8ef66dd4a@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Before the io-wq thread change, we maintained a hash work map and lock
per-node per-ring. That wasn't ideal, as we really wanted it to be per
ring. But now that we have per-task workers, the hash map ends up being
just per-task. That'll work just fine for the normal case of having
one task use a ring, but if you share the ring between tasks, then it's
considerably worse than it was before.
Make the hash map per ctx instead, which provides full per-ctx buffered
write serialization on hashed writes.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This reverts commit 88f171ab77.
I ran into a case where the ref resurrect now spins, so revert
this change for now until we can further investigate why it's
broken. The bug seems to indicate spinning on the lock itself,
likely there's some ABBA deadlock involved:
[<0>] __percpu_ref_switch_mode+0x45/0x180
[<0>] percpu_ref_resurrect+0x46/0x70
[<0>] io_refs_resurrect+0x25/0xa0
[<0>] __io_uring_register+0x135/0x10c0
[<0>] __x64_sys_io_uring_register+0xc2/0x1a0
[<0>] do_syscall_64+0x42/0x110
[<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the task ends up doing no IO, the context list is empty and we don't
call into __io_uring_files_cancel() when the task exits. This can cause
a leak of the io-wq structures.
Ensure we always call __io_uring_files_cancel(), even if the task
context list is empty.
Fixes: 5aa75ed5b9 ("io_uring: tie async worker side to the task context")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
At this point we're only using it for memory accounting, so there's no
need to have an extra ->limit_mem - we can just set ->user if we do
the accounting, or leave it at NULL if we don't.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We're now just using fork like we would from userspace, so there's no
need to try and impose extra restrictions or accounting on the user
side of things. That's already being done for us. That also means we
don't have to pass in the user_struct anymore, that's correctly inherited
through ->creds on fork.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A few reasons to do this:
- The naming of the manager and worker have changed. That's a user visible
change, so makes sense to flag it.
- Opening certain files that use ->signal (like /proc/self or /dev/tty)
now works, and the flag tells the application upfront that this is the
case.
- Related to the above, using signalfd will now work as well.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't forget to zero locked_free_nr, it's not a disaster but makes it
attempting to flush it with extra locking when there is nothing in the
list. Also, don't traverse a potentially long list freeing requests
under spinlock, splice the list and do it afterwards.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're exiting the ring, just let the IO fail with -EAGAIN as nobody
will care anyway. It's not the right context to reissue from.
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't use a kthread for SQPOLL, use a forked worker just like the io-wq
workers. With that done, we can drop the various context grabbing we do
for SQPOLL, it already has everything it needs.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The async workers are siblings of the task itself, so by definition we
have all the state that we need. Remove any of the state grabbing that
we have, and requests flagging what they need.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of using regular kthread kernel threads, create kernel threads
that are like a real thread that the task would create. This ensures that
we get all the context that we need, without having to carry that state
around. This greatly reduces the code complexity, and the risk of missing
state for a given request type.
With the move away from kthread, we can also dump everything related to
assigned state to the new threads.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Moving towards making the io_wq per ring per task, so we can't really
share it between rings. Which is fine, since we've now dropped some
of that fat from it.
Retain compatibility with how attaching works, so that any attempt to
attach to an fd that doesn't exist, or isn't an io_uring fd, will fail
like it did before.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We hit this case when the task is exiting, and we need somewhere to
do background cleanup of requests. Instead of relying on the io-wq
task manager to do this work for us, just stuff it somewhere where
we can safely run it ourselves directly.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* for-5.12/io_uring: (21 commits)
io_uring: run task_work on io_uring_register()
io_uring: fix leaving invalid req->flags
io_uring: wait potential ->release() on resurrect
io_uring: keep generic rsrc infra generic
io_uring: zero ref_node after killing it
io_uring: make the !CONFIG_NET helpers a bit more robust
io_uring: don't hold uring_lock when calling io_run_task_work*
io_uring: fail io-wq submission from a task_work
io_uring: don't take uring_lock during iowq cancel
io_uring: fail links more in io_submit_sqe()
io_uring: don't do async setup for links' heads
io_uring: do io_*_prep() early in io_submit_sqe()
io_uring: split sqe-prep and async setup
io_uring: don't submit link on error
io_uring: move req link into submit_state
io_uring: move io_init_req() into io_submit_sqe()
io_uring: move io_init_req()'s definition
io_uring: don't duplicate ->file check in sfr
io_uring: keep io_*_prep() naming consistent
io_uring: kill fictitious submit iteration index
...
Do run task_work before io_uring_register(), that might make a first
quiesce round much nicer. We generally do that for any syscall invocation
to avoid spurious -EINTR/-ERESTARTSYS, for task_work that we generate.
This patch brings io_uring_register() inline with the two other io_uring
syscalls.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.12/io_uring-2021-02-17' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
"Highlights from this cycles are things like request recycling and
task_work optimizations, which net us anywhere from 10-20% of speedups
on workloads that mostly are inline.
This work was originally done to put io_uring under memcg, which adds
considerable overhead. But it's a really nice win as well. Also worth
highlighting is the LOOKUP_CACHED work in the VFS, and using it in
io_uring. Greatly speeds up the fast path for file opens.
Summary:
- Put io_uring under memcg protection. We accounted just the rings
themselves under rlimit memlock before, now we account everything.
- Request cache recycling, persistent across invocations (Pavel, me)
- First part of a cleanup/improvement to buffer registration (Bijan)
- SQPOLL fixes (Hao)
- File registration NULL pointer fixup (Dan)
- LOOKUP_CACHED support for io_uring
- Disable /proc/thread-self/ for io_uring, like we do for /proc/self
- Add Pavel to the io_uring MAINTAINERS entry
- Tons of code cleanups and optimizations (Pavel)
- Support for skip entries in file registration (Noah)"
* tag 'for-5.12/io_uring-2021-02-17' of git://git.kernel.dk/linux-block: (103 commits)
io_uring: tctx->task_lock should be IRQ safe
proc: don't allow async path resolution of /proc/thread-self components
io_uring: kill cached requests from exiting task closing the ring
io_uring: add helper to free all request caches
io_uring: allow task match to be passed to io_req_cache_free()
io-wq: clear out worker ->fs and ->files
io_uring: optimise io_init_req() flags setting
io_uring: clean io_req_find_next() fast check
io_uring: don't check PF_EXITING from syscall
io_uring: don't split out consume out of SQE get
io_uring: save ctx put/get for task_work submit
io_uring: don't duplicate io_req_task_queue()
io_uring: optimise SQPOLL mm/files grabbing
io_uring: optimise out unlikely link queue
io_uring: take compl state from submit state
io_uring: inline io_complete_rw_common()
io_uring: move res check out of io_rw_reissue()
io_uring: simplify iopoll reissuing
io_uring: clean up io_req_free_batch_finish()
io_uring: move submit side state closer in the ring
...
sqe->flags are subset of req flags, so incorrectly copied may span into
in-kernel flags and wreck havoc, e.g. by setting REQ_F_INFLIGHT.
Fixes: 5be9ad1e42 ("io_uring: optimise io_init_req() flags setting")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is a short window where percpu_refs are already turned zero, but
we try to do resurrect(). Play nicer and wait for ->release() to happen
in this case and proceed as everything is ok. One downside for ctx refs
is that we can ignore signal_pending() on a rare occasion, but someone
else should check for it later if needed.
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_rsrc_ref_quiesce() is a generic resource function, though now it
was wired to allocate and initialise ref nodes with file-specific
callbacks/etc. Keep it sane by passing in as a parameters everything we
need for initialisations, otherwise it will hurt us badly one day.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After a rsrc/files reference node's refs are killed, it must never be
used. And that's how it works, it either assigns a new node or kills the
whole data table.
Let's explicitly NULL it, that shouldn't be necessary, but if something
would go wrong I'd rather catch a NULL dereference to using a dangling
pointer.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With the prep and prep async split, we now have potentially 3 helpers
that need to be defined for !CONFIG_NET. Add some helpers to do just
that.
Fixes the following compile error on !CONFIG_NET:
fs/io_uring.c:6171:10: error: implicit declaration of function
'io_sendmsg_prep_async'; did you mean 'io_req_prep_async'?
[-Werror=implicit-function-declaration]
return io_sendmsg_prep_async(req);
^~~~~~~~~~~~~~~~~~~~~
io_req_prep_async
Fixes: 93642ef884 ("io_uring: split sqe-prep and async setup")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In case of failure io_wq_submit_work() needs to post an CQE and so
potentially take uring_lock. The safest way to deal with it is to do
that from under task_work where we can safely take the lock.
Also, as io_iopoll_check() holds the lock tight and releases it
reluctantly, it will play nicer in the furuter with notifying an
iopolling task about new such pending failed requests.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of marking a link with REQ_F_FAIL_LINK on an error and delaying
its failing to the caller, do it eagerly right when after getting an
error in io_submit_sqe(). This renders FAIL_LINK checks in
io_queue_link_head() useless and we can skip it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now, as we can do async setup without holding an SQE, we can skip doing
io_req_defer_prep() for link heads, it will be tried to be executed
inline and follows all the rules of the non-linked requests.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now as preparations are split from async setup, we can do the first one
pretty early not spilling it across multiple call sites. And after it's
done SQE is not needed anymore and we can save on passing it deeply into
the submission stack.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are two kinds of opcode-specific preparations we do. The first is
just initialising req with what is always needed for an opcode and
reading all non-generic SQE fields. And the second is copying some of
the stuff like iovec preparing to punt a request to somewhere async,
e.g. to io-wq or for draining. For requests that have tried an inline
execution but still needing to be punted, the second prep type is done
by the opcode handler itself.
Currently, we don't explicitly split those preparation steps, but
combining both of them into io_*_prep(), altering the behaviour by
allocating ->async_data. That's pretty messy and hard to follow and also
gets in the way of some optimisations.
Split the steps, leave the first type as where it is now, and put the
second into a new io_req_prep_async() helper. It may make us to do opcode
switch twice, but it's worth it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we get an error in io_init_req() for a request that would have been
linked, we break the submission but still issue a partially composed
link, that's nasty, fail it instead.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move struct io_submit_link into submit_state, which is a part of a
submission state and so belongs to it. It saves us from explicitly
passing it, and init/deinit is now nicely hidden in
io_submit_state_[start,end].
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Behaves identically, just move io_init_req() call into the beginning of
io_submit_sqes(). That looks better unloads io_submit_sqes().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A preparation patch, symbol to symbol move io_init_req() +
io_check_restriction() a bit up. The submission path is pretty settled
down, so don't worry about backports and move the functions instead of
relying on forward declarations in the future.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_SYNC_FILE_RANGE is marked as .needs_file, so the common path
will take care of assigning and validating req->file, no need to
duplicate it in io_sfr_prep().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Follow io_*_prep() naming pattern, there are only fsync and sfr that
don't do that.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
@i and @submitted are very much coupled together, and there is no need
to keep them both. Remove @i, it doesn't change generated binary but
helps to keep a single source of truth.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't forget to free iovec read inline completion and bunch of other
cases that do "goto done" before setting up an async context.
Fixes: 5ea5dd4584 ("io_uring: inline io_read()'s iovec freeing")
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We add task_work from any context, hence we need to ensure that we can
tolerate it being from IRQ context as well.
Fixes: 7cbf1722d5 ("io_uring: provide FIFO ordering for task_work")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Be nice and prune these upfront, in case the ring is being shared and
one of the tasks is going away. This is a bit more important now that
we account the allocations.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have three different ones, put it in a helper for easy calling. This
is in preparation for doing it outside of ring freeing as well. With
that in mind, also ensure that we do the proper locking for safe calling
from a context where the ring it still live.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
No changes in this patch, just allows a caller to pass in a targeted
task that we must match for freeing requests in the cache.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Invalid req->flags are tolerated by free/put well, avoid this dancing
needlessly presetting it to zero, and then not even resetting but
modifying it, i.e. "|=".
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Indirectly io_req_find_next() is called for every request, optimise the
check by testing flags as it was long before -- __io_req_find_next()
tolerates false-positives well (i.e. link==NULL), and those should be
really rare.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_sq_thread_acquire_mm_files() can find a PF_EXITING task only when
it's called from task_work context. Don't check it in all other cases,
that are when we're in io_uring_enter().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove io_consume_sqe() and inline it back into io_get_sqe(). It
requires req dealloc on error, but in exchange we get cleaner
io_submit_sqes() and better locality for cached_sq_head.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Do a little trick in io_ring_ctx_free() briefly taking uring_lock, that
will wait for everyone currently holding it, so we can skip pinning ctx
with ctx->refs for __io_req_task_submit(), which is executed and loses
its refs/reqs while holding the lock.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't hand code io_req_task_queue() inside of io_async_buf_func(), just
call it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There are two reasons for this. First is to optimise
io_sq_thread_acquire_mm_files() for non-SQPOLL case, which currently do
too many checks and function calls in the hot path, e.g. in
io_init_req().
The second is to not grab mm/files when there are not needed. As
__io_queue_sqe() issues only one request now, we can reuse
io_sq_thread_acquire_mm_files() instead of unconditional acquire
mm/files.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_queue_sqe() tries to issue as much requests of a link as it can,
and uses io_put_req_find_next() to extract a next one, targeting inline
completed requests. As now __io_queue_sqe() is always used together with
struct io_comp_state, it leaves next propagation only a small window and
only for async reqs, that doesn't justify its existence.
Remove it, make __io_queue_sqe() to issue only a head request. It
simplifies the code and will allow other optimisations.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Completion and submission states are now coupled together, it's weird to
get one from argument and another from ctx, do it consistently for
io_req_free_batch(). It's also faster as we already have @state cached
in registers.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_complete_rw() casts request to kiocb for it to be immediately
container_of()'ed by io_complete_rw_common(). And the last function's name
doesn't do a great job of illuminating its purposes, so just inline it in
its only user.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We pass return code into io_rw_reissue() only to be able to check if it's
-EAGAIN. That's not the cleanest approach and may prevent inlining of the
non-EAGAIN fast path, so do it at call sites.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't stash -EAGAIN'ed iopoll requests into a list to reissue it later,
do it eagerly. It removes overhead on keeping and checking that list,
and allows in case of failure for these requests to be completed through
normal iopoll completion path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_req_free_batch_finish() is final and does not permit struct req_batch
to be reused without re-init. To be more consistent don't clear ->task
there.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We recently added the submit side req cache, but it was placed at the
end of the struct. Move it near the other submission state for better
memory placement, and reshuffle a few other members at the same time.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We use the assigned slot in io_sqe_file_register(), and a previous
patch moved the assignment to after we have called it. This isn't
super pretty, and will get cleaned up in the future. For now, fix
the regression by restoring the previous assignment/clear of the
file_slot.
Fixes: ea64ec02b3 ("io_uring: deduplicate file table slot calculation")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The variable ret is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.
Addresses-Coverity: ("Unused value")
Fixes: b63534c41e ("io_uring: re-issue block requests that failed because of resources")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We park SQPOLL task before going into io_uring_cancel_files(), so the
task won't run task_works including those that might be important for
the cancellation passes. In this case it's io_poll_remove_one(), which
frees requests via io_put_req_deferred().
Unpark it for while waiting, it's ok as we disable submissions
beforehand, so no new requests will be generated.
INFO: task syz-executor893:8493 blocked for more than 143 seconds.
Call Trace:
context_switch kernel/sched/core.c:4327 [inline]
__schedule+0x90c/0x21a0 kernel/sched/core.c:5078
schedule+0xcf/0x270 kernel/sched/core.c:5157
io_uring_cancel_files fs/io_uring.c:8912 [inline]
io_uring_cancel_task_requests+0xe70/0x11a0 fs/io_uring.c:8979
__io_uring_files_cancel+0x110/0x1b0 fs/io_uring.c:9067
io_uring_files_cancel include/linux/io_uring.h:51 [inline]
do_exit+0x2fe/0x2ae0 kernel/exit.c:780
do_group_exit+0x125/0x310 kernel/exit.c:922
__do_sys_exit_group kernel/exit.c:933 [inline]
__se_sys_exit_group kernel/exit.c:931 [inline]
__x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Cc: stable@vger.kernel.org # 5.5+
Reported-by: syzbot+695b03d82fa8e4901b06@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This reverts commit 10cad2c40d.
Petr reports that with this commit in place, io_uring fails the chroot
test (CVE-202-29373). We do need to retain ->fs for send/recvmsg, so
revert this commit.
Reported-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of imposing rlimit memlock limits for the rings themselves,
ensure that we account them properly under memcg with __GFP_ACCOUNT.
We retain rlimit memlock for registered buffers, this is just for the
ring arrays themselves.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is the last class of requests that cannot utilize the req alloc
cache. Add a per-ctx req cache that is protected by the completion_lock,
and refill our submit side cache when it gets over our batch count.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Awhile there are requests in the allocation cache -- use them, only if
those ended go for the stashed memory in comp.free_list. As list
manipulation are generally heavy and are not good for caches, flush them
all or as much as can in one go.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: return success/failure from io_flush_cached_reqs()]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_queue_sqe() is always called with a non-NULL comp_state, which is
taken directly from context. Don't pass it around but infer from ctx.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
task_work is run without utilizing the req alloc cache, so any deferred
items don't get to take advantage of either the alloc or free side of it.
With task_work now being wrapped by io_uring, we can use the ctx
completion state to both use the req cache and the completion flush
batching.
With this, the only request type that cannot take advantage of the req
cache is IRQ driven IO for regular files / block devices. Anything else,
including IOPOLL polled IO to those same tyes, will take advantage of it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
task_work is a LIFO list, due to how it's implemented as a lockless
list. For long chains of task_work, this can be problematic as the
first entry added is the last one processed. Similarly, we'd waste
a lot of CPU cycles reversing this list.
Wrap the task_work so we have a single task_work entry per task per
ctx, and use that to run it in the right order.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that we have the submit_state in the ring itself, we can have io_kiocb
allocations that are persistent across invocations. This reduces the time
spent doing slab allocations and frees.
[sil: rebased]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make io_req_free_batch(), which is used for inline executed requests and
IOPOLL, to return requests back into the allocation cache, so avoid
most of kmalloc()/kfree() for those cases.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently batch free handles request memory freeing and ctx ref putting
together. Separate them and use different counters, that will be needed
for reusing reqs memory.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove fallback_req for now, it gets in the way of other changes.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_submit_flush_completions() does completion batching, but may also use
free batching as iopoll does. The main beneficiaries should be buffered
reads/writes and send/recv.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reincarnation of an old patch that replaces a list in struct
io_compl_batch with an array. It's needed to avoid hooking requests via
their compl.list, because it won't be always available in the future.
It's also nice to split io_submit_flush_completions() to avoid free
under locks and remove unlock/lock with a long comment describing when
it can be done.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As now submit_state is retained across syscalls, we can save ourself
from initialising it from ground up for each io_submit_sqes(). Set some
fields during ctx allocation, and just keep them always consistent.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: remove unnecessary zeroing of ctx members]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
completion state is closely bound to ctx, we don't need to store ctx
inside as we always have it around to pass to flush.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct io_submit_state is quite big (168 bytes) and going to grow. It's
better to not keep it on stack as it is now. Move it to context, it's
always protected by uring_lock, so it's fine to have only one instance
of it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no reason to drag io_comp_state into opcode handlers, we just
need a flag and the actual work will be done in __io_queue_sqe().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make opcode handler interfaces a bit more consistent by always passing
in issue flags. Bulky but pretty easy and mechanical change.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace bool force_nonblock with flags. It has a long standing goal of
differentiating context from which we execute. Currently we have some
subtle places where some invariants, like holding of uring_lock, are
subtly inferred.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For SQPOLL rings tctx_inflight() always returns zero, so it might skip
doing full cancelation. It's fine because we jam all sqpoll submissions
in any case and do go through files cancel for them, but not nice.
Do the intended full cancellation, by mimicking __io_uring_task_cancel()
waiting but impersonating SQPOLL task.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Current iov handling with recvmsg/sendmsg may be confusing. First make a
rule for msg->iov: either it points to an allocated iov that have to be
kfree()'d later, or it's NULL and we use fast_iov. That's much better
than current 3-state (also can point to fast_iov). And rename it into
free_iov for uniformity with read/write.
Also, instead of after struct io_async_msghdr copy fixing up of
msg.msg_iter.iov has been happening in io_recvmsg()/io_sendmsg(). Move
it into io_setup_async_msg(), that's the right place.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: add comment on NULL check before kfree()]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Don't pretend we don't know that REQ_F_BUFFER_SELECT for recvmsg always
uses fast_iov -- clean up confusing intermixing kmsg->iov and
kmsg->fast_iov for buffer select.
Also don't init iter with garbage in __io_recvmsg_copy_hdr() only for it
to be set shortly after in io_recvmsg().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_setup_async_msg() should fully prepare io_async_msghdr, let it also
handle assigning msg_name and don't hand code it in [send,recv]msg().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since SQPOLL task can be shared and so task_work entries can be a mix of
them, we need to drop mm and files before trying to issue next request.
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Saving one lock/unlock for io-wq is not super important, but adds some
ugliness in the code. More important, atomic decs not turning it to zero
for some archs won't give the right ordering/barriers so the
io_steal_work() may pretty easily get subtly and completely broken.
Return back 2-step io-wq work exchange and clean it up.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Extract a helper io_fixed_file_slot() returning a place in our fixed
files table, so we don't hand-code it three times in the code.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_import_iovec() doesn't return IO size anymore, only error code. Make
it more apparent by returning int instead of ssize and clean up
leftovers.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make decision making of whether we need to retry read/write similar for
O_NONBLOCK and RWF_NOWAIT. Set REQ_F_NOWAIT when either is specified and
use it for all relevant checks. Also fix resubmitting NOWAIT requests
via io_rw_reissue().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We already have implicit do-while for read-retries but with goto in the
end. Convert it to an actual do-while, it highlights it so making a
bit more understandable and is cleaner in general.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_read() has not the simpliest control flow with a lot of jumps and
it's hard to read. One of those is a out_free: label, which frees iovec.
However, from the middle of io_read() iovec is NULL'ed and so
kfree(iovec) is no-op, it leaves us with two place where we can inline
it and further clean up the code.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have invariant in io_read() of how much we're trying to read spilled
into an iter and io_size variable. The last one controls decision making
about whether to do read-retries. However, io_size is modified only
after the first read attempt, so if we happen to go for a third retry in
a single call to io_read(), we will get io_size greater than in the
iterator, so may lead to various side effects up to live-locking.
Modify io_size each time.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now we give out ownership of iovec into io_setup_async_rw(), so it
either sets request's context right or frees the iovec on error itself.
Makes our life a bit easier at call sites.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
First, instead of checking iov_iter_count(iter) for 0 to find out that
all needed bytes were read, just compare returned code against io_size.
It's more reliable and arguably cleaner.
Also, place the half-read case into an else branch and delete an extra
label.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
!io_file_supports_async() case of io_read() is hard to read, it jumps
somewhere in the middle of the function just to do async setup and fail
on a similar check. Call io_setup_async_rw() directly for this case,
it's much easier to follow.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's easy to make a mistake in io_cqring_wait() because for all
break/continue clauses we need to watch for prepare/finish_wait to be
used correctly. Extract all those into a new helper
io_cqring_wait_schedule(), and transforming the loop into simple series
of func calls: prepare(); check_and_schedule(); finish();
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
schedule_timeout() with timeout=MAX_SCHEDULE_TIMEOUT is guaranteed to
work just as schedule(), so instead of hand-coding it based on arguments
always use the timeout version and simplify code.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Files and task cancellations go over same steps trying to cancel
requests in io-wq, poll, etc. Deduplicate it with a helper.
note: new io_uring_try_cancel_requests() is former
__io_uring_cancel_task_requests() with files passed as an agrument and
flushing overflowed requests.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
do_read() returning 0 bytes read (not -EAGAIN/etc.) is not an important
enough of a case to prioritise it. Fold it into ret < 0 check, so we get
rid of an extra if and make it a bit more readable.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't know for how long REQ_F_INFLIGHT is going to stay, cleaner to
extract a helper for marking requests as so.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Shouldn't be a problem now, but it's better to clean
REQ_F_WORK_INITIALIZED and work->flags only after relevant resources are
killed, so cancellation see them.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
req->files now have same lifetime as all other iowq-work resources,
inline io_req_drop_files() for consistency. Moreover, since
REQ_F_INFLIGHT is no more files specific, the function name became
very confusing.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have no request types left using needs_file_no_error, remove it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we hit a "goto out_free;" before the "ctx->file_data" pointer has
been assigned then it leads to a NULL derefence when we call:
free_fixed_rsrc_data(ctx->file_data);
We can fix this by moving the assignment earlier.
Fixes: 1ad555c6ae ("io_uring: create common fixed_rsrc_data allocation routines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds support for skipping a file descriptor when using
IORING_REGISTER_FILES_UPDATE. __io_sqe_files_update will skip fds set
to IORING_REGISTER_FILES_SKIP. IORING_REGISTER_FILES_SKIP is inturn
added as a #define in io_uring.h
Signed-off-by: noah <goldstein.w.n@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Replace a while with a simple for loop, that looks way more natural, and
enables us to use "continue" as indexes are no more updated by hand in
the end of the loop.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We grab a task for each request and while putting it it also have to do
extra work like inflight accounting and waking up that task. This
sequence is duplicated several time, it's good time to add a helper.
More to that, the helper generates better code due to better locality
and so not failing alias analysis.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For SQPOLL io_uring we want to have only one file note held by
sqo_task. Add a warning to make sure it holds. It's deep in
io_uring_add_task_file() out of hot path, so shouldn't hurt.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The function io_remove_personalities() is very similar to
io_unregister_personality(),so implement io_remove_personalities()
calling io_unregister_personality().
Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently split the close into two, in case we have a ->flush op
that we can't safely handle from non-blocking context. This requires
us to flag the op as uncancelable if we do need to punt it async, and
that means special handling for just this op type.
Use __close_fd_get_file() and grab the files lock so we can get the file
and check if we need to go async in one atomic operation. That gets rid
of the need for splitting this into two steps, and hence the need for
IO_WQ_WORK_NO_CANCEL.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a request is completed with comp_state, its completion reference
put is deferred to io_submit_flush_completions(), but the submission
is put not far from there, so do it together to save one atomic dec per
request. That targets requests that complete inline, e.g. buffered rw,
send/recv.
Proper benchmarking haven't been conducted but for nops(batch=32) it was
around 7901 vs 8117 KIOPS (~2.7%), or ~4% per perf profiling.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_submit_flush_completions() is called down the stack in the _state
version of io_req_complete(), that's ok because is only called by
io_uring opcode handler functions directly. Move it up to
__io_queue_sqe() as preparation.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_req_complete() inlining is a bit weird, some compilers don't
optimise out the non-NULL branch of it even when called as
io_req_complete(). Help it a bit by extracting state and stateless
helpers out of __io_req_complete().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Deduplicates translation of timeout flags into hrtimer_mode.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When io_req_task_work_add() fails, the request will be cancelled by
enqueueing via task_works of io-wq. Extract a function for that.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The check in io_state_file_put() is optimised pretty well when called
from __io_file_get(). Don't pollute the code with all these variants.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Get rid of a label in io_alloc_req(), it's cleaner to do return
directly.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Apparently, there is one more place hand coded calculation of number of
CQ events in the ring. Use __io_cqring_events() helper in
io_get_cqring() as well. Naturally, assembly stays identical.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The name is confusing and it's used only in one place.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
personality_idr is usually synchronised by uring_lock, the exception
would be removing personalities in io_ring_ctx_wait_and_kill(), which
is legit as refs are killed by that point but still would be more
resilient to do it under the lock.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's awkward to pass return a value into a function for it to return it
back. Check it at the caller site and clean up io_resubmit_prep() a bit.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The hot path is IO completing on the first try. Reshuffle io_rw_reissue() so
it's checked first.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make the percpu ref release function names consistent between rsrc data
and nodes.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Create common alloc/free fixed_rsrc_data routines for both files and
buffers.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[remove buffer part]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Create common routines to be used for both files/buffers registration.
[remove io_sqe_rsrc_set_node substitution]
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[merge, quiesce only for files]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A simple prep patch allowing to set refnode callbacks after it was
allocated. This needed to 1) keep ourself off of hi-level functions
where it's not pretty and they are not necessary 2) amortise ref_node
allocation in the future, e.g. for updates.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Split alloc_fixed_file_ref_node into resource generic/specific parts,
to be leveraged for fixed buffers.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Uplevel ref_list and make it common to all resources. This is to
allow one common ref_list to be used for both files, and buffers
in upcoming patches.
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Generalize io_queue_rsrc_removal to handle both files and buffers.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[remove io_mapped_ubuf from rsrc tables/etc. for now]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This is a prep rename patch for subsequent patches to generalize file
registration.
[io_uring_rsrc_update:: rename fds -> data]
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
[leave io_uring_files_update as struct]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move allocation of buffer management structures, and validation of
buffers into separate routines.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Split io_sqe_buffer_register into two routines:
- io_sqe_buffer_register() registers a single buffer
- io_sqe_buffers_register iterates over all user specified buffers
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of being pessimistic and assume that path lookup will block, use
LOOKUP_CACHED to attempt just a cached lookup. This ensures that the
fast path is always done inline, and we only punt to async context if
IO is needed to satisfy the lookup.
For forced nonblock open attempts, mark the file O_NONBLOCK over the
actual ->open() call as well. We can safely clear this again before
doing fd_install(), so it'll never be user visible that we fiddled with
it.
This greatly improves the performance of file open where the dentry is
already cached:
ached 5.10-git 5.10-git+LOOKUP_CACHED Speedup
---------------------------------------------------------------
33% 1,014,975 900,474 1.1x
89% 545,466 292,937 1.9x
100% 435,636 151,475 2.9x
The more cache hot we are, the faster the inline LOOKUP_CACHED
optimization helps. This is unsurprising and expected, as a thread
offload becomes a more dominant part of the total overhead. If we look
at io_uring tracing, doing an IORING_OP_OPENAT on a file that isn't in
the dentry cache will yield:
275.550481: io_uring_create: ring 00000000ddda6278, fd 3 sq size 8, cq size 16, flags 0
275.550491: io_uring_submit_sqe: ring 00000000ddda6278, op 18, data 0x0, non block 1, sq_thread 0
275.550498: io_uring_queue_async_work: ring 00000000ddda6278, request 00000000c0267d17, flags 69760, normal queue, work 000000003d683991
275.550502: io_uring_cqring_wait: ring 00000000ddda6278, min_events 1
275.550556: io_uring_complete: ring 00000000ddda6278, user_data 0x0, result 4
which shows a failed nonblock lookup, then punt to worker, and then we
complete with fd == 4. This takes 65 usec in total. Re-running the same
test case again:
281.253956: io_uring_create: ring 0000000008207252, fd 3 sq size 8, cq size 16, flags 0
281.253967: io_uring_submit_sqe: ring 0000000008207252, op 18, data 0x0, non block 1, sq_thread 0
281.253973: io_uring_complete: ring 0000000008207252, user_data 0x0, result 4
shows the same request completing inline, also returning fd == 4. This
takes 6 usec.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
What 84965ff8a8 ("io_uring: if we see flush on exit, cancel related tasks")
really wants is to cancel all relevant REQ_F_INFLIGHT requests reliably.
That can be achieved by io_uring_cancel_files(), but we'll miss it
calling io_uring_cancel_task_requests(files=NULL) from io_uring_flush(),
because it will go through __io_uring_cancel_task_requests().
Just always call io_uring_cancel_files() during cancel, it's good enough
for now.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: CPU: 0 PID: 21359 at fs/io_uring.c:9042
io_uring_cancel_task_requests+0xe55/0x10c0 fs/io_uring.c:9042
Call Trace:
io_uring_flush+0x47b/0x6e0 fs/io_uring.c:9227
filp_close+0xb4/0x170 fs/open.c:1295
close_files fs/file.c:403 [inline]
put_files_struct fs/file.c:418 [inline]
put_files_struct+0x1cc/0x350 fs/file.c:415
exit_files+0x7e/0xa0 fs/file.c:435
do_exit+0xc22/0x2ae0 kernel/exit.c:820
do_group_exit+0x125/0x310 kernel/exit.c:922
get_signal+0x427/0x20f0 kernel/signal.c:2773
arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
handle_signal_work kernel/entry/common.c:147 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Now io_uring_cancel_task_requests() can be called not through file
notes but directly, remove a WARN_ONCE() there that give us false
positives. That check is not very important and we catch it in other
places.
Fixes: 84965ff8a8 ("io_uring: if we see flush on exit, cancel related tasks")
Cc: stable@vger.kernel.org # 5.9+
Reported-by: syzbot+3e3d9bd0c6ce9efbc3ef@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the tctx inflight number haven't changed because of cancellation,
__io_uring_task_cancel() will continue leaving the task in
TASK_UNINTERRUPTIBLE state, that's not expected by
__io_uring_files_cancel(). Ensure we always call finish_wait() before
retrying.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This normally doesn't cause any extra harm, but it does mean that we'll
increment the eventfd notification count, if one has been registered
with the ring. This can confuse applications, when they see more
notifications on the eventfd side than are available in the ring.
Do the nice thing and only increment this count, if we actually posted
(or even overflowed) events.
Reported-and-tested-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ensure we match tasks that belong to a dead or dying task as well, as we
need to reap those in addition to those belonging to the exiting task.
Cc: stable@vger.kernel.org # 5.9+
Reported-by: Josef Grieb <josef.grieb@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We need to actively cancel anything that introduces a potential circular
loop, where io_uring holds a reference to itself. If the file in question
is an io_uring file, then add the request to the inflight list.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Sockets and other non-regular files may actually expect short reads to
happen, don't retry reads for them. Because non-reg files don't set
FMODE_BUF_RASYNC and so it won't do second/retry do_read, we can filter
out those cases after first do_read() attempt with ret>0.
Cc: stable@vger.kernel.org # 5.9+
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_OP_CLOSE is special in terms of cancelation, since it has an
intermediate state where we've removed the file descriptor but hasn't
closed the file yet. For that reason, it's currently marked with
IO_WQ_WORK_NO_CANCEL to prevent cancelation. This ensures that the op
is always run even if canceled, to prevent leaving us with a live file
but an fd that is gone. However, with SQPOLL, since a cancel request
doesn't carry any resources on behalf of the request being canceled, if
we cancel before any of the close op has been run, we can end up with
io-wq not having the ->files assigned. This can result in the following
oops reported by Joseph:
BUG: kernel NULL pointer dereference, address: 00000000000000d8
PGD 800000010b76f067 P4D 800000010b76f067 PUD 10b462067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 1 PID: 1788 Comm: io_uring-sq Not tainted 5.11.0-rc4 #1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:__lock_acquire+0x19d/0x18c0
Code: 00 00 8b 1d fd 56 dd 08 85 db 0f 85 43 05 00 00 48 c7 c6 98 7b 95 82 48 c7 c7 57 96 93 82 e8 9a bc f5 ff 0f 0b e9 2b 05 00 00 <48> 81 3f c0 ca 67 8a b8 00 00 00 00 41 0f 45 c0 89 04 24 e9 81 fe
RSP: 0018:ffffc90001933828 EFLAGS: 00010002
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000000000d8
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888106e8a140 R15: 00000000000000d8
FS: 0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000d8 CR3: 0000000106efa004 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x31a/0x440
? close_fd_get_file+0x39/0x160
? __lock_acquire+0x647/0x18c0
_raw_spin_lock+0x2c/0x40
? close_fd_get_file+0x39/0x160
close_fd_get_file+0x39/0x160
io_issue_sqe+0x1334/0x14e0
? lock_acquire+0x31a/0x440
? __io_free_req+0xcf/0x2e0
? __io_free_req+0x175/0x2e0
? find_held_lock+0x28/0xb0
? io_wq_submit_work+0x7f/0x240
io_wq_submit_work+0x7f/0x240
io_wq_cancel_cb+0x161/0x580
? io_wqe_wake_worker+0x114/0x360
? io_uring_get_socket+0x40/0x40
io_async_find_and_cancel+0x3b/0x140
io_issue_sqe+0xbe1/0x14e0
? __lock_acquire+0x647/0x18c0
? __io_queue_sqe+0x10b/0x5f0
__io_queue_sqe+0x10b/0x5f0
? io_req_prep+0xdb/0x1150
? mark_held_locks+0x6d/0xb0
? mark_held_locks+0x6d/0xb0
? io_queue_sqe+0x235/0x4b0
io_queue_sqe+0x235/0x4b0
io_submit_sqes+0xd7e/0x12a0
? _raw_spin_unlock_irq+0x24/0x30
? io_sq_thread+0x3ae/0x940
io_sq_thread+0x207/0x940
? do_wait_intr_irq+0xc0/0xc0
? __ia32_sys_io_uring_enter+0x650/0x650
kthread+0x134/0x180
? kthread_create_worker_on_cpu+0x90/0x90
ret_from_fork+0x1f/0x30
Fix this by moving the IO_WQ_WORK_NO_CANCEL until _after_ we've modified
the fdtable. Canceling before this point is totally fine, and running
it in the io-wq context _after_ that point is also fine.
For 5.12, we'll handle this internally and get rid of the no-cancel
flag, as IORING_OP_CLOSE is the only user of it.
Cc: stable@vger.kernel.org
Fixes: b5dba59e0c ("io_uring: add support for IORING_OP_CLOSE")
Reported-by: "Abaci <abaci@linux.alibaba.com>"
Reviewed-and-tested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If there are no requests at the time __io_uring_task_cancel() is called,
tctx_inflight() returns zero and and it terminates not getting a chance
to go through __io_uring_files_cancel() and do
io_disable_sqo_submit(). And we absolutely want them disabled by the
time cancellation ends.
Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Fixes: d9d05217cb ("io_uring: stop SQPOLL submit on creator's death")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: CPU: 1 PID: 11100 at fs/io_uring.c:9096
io_uring_flush+0x326/0x3a0 fs/io_uring.c:9096
RIP: 0010:io_uring_flush+0x326/0x3a0 fs/io_uring.c:9096
Call Trace:
filp_close+0xb4/0x170 fs/open.c:1280
close_files fs/file.c:401 [inline]
put_files_struct fs/file.c:416 [inline]
put_files_struct+0x1cc/0x350 fs/file.c:413
exit_files+0x7e/0xa0 fs/file.c:433
do_exit+0xc22/0x2ae0 kernel/exit.c:820
do_group_exit+0x125/0x310 kernel/exit.c:922
get_signal+0x3e9/0x20a0 kernel/signal.c:2770
arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:811
handle_signal_work kernel/entry/common.c:147 [inline]
exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
exit_to_user_mode_prepare+0x148/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
entry_SYSCALL_64_after_hwframe+0x44/0xa9
An SQPOLL ring creator task may have gotten rid of its file note during
exit and called io_disable_sqo_submit(), but the io_uring is still left
referenced through fdtable, which will be put during close_files() and
cause a false positive warning.
First split the warning into two for more clarity when is hit, and the
add sqo_dead check to handle the described case.
Reported-by: syzbot+a32b546d58dde07875a1@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: CPU: 1 PID: 9094 at fs/io_uring.c:8884
io_disable_sqo_submit+0x106/0x130 fs/io_uring.c:8884
Call Trace:
io_uring_flush+0x28b/0x3a0 fs/io_uring.c:9099
filp_close+0xb4/0x170 fs/open.c:1280
close_fd+0x5c/0x80 fs/file.c:626
__do_sys_close fs/open.c:1299 [inline]
__se_sys_close fs/open.c:1297 [inline]
__x64_sys_close+0x2f/0xa0 fs/open.c:1297
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
io_uring's final close() may be triggered by any task not only the
creator. It's well handled by io_uring_flush() including SQPOLL case,
though a warning in io_disable_sqo_submit() will fallaciously fire by
moving this warning out to the only call site that matters.
Reported-by: syzbot+2f5d1785dc624932da78@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're freeing/finishing iopoll requests, ensure we check if the task
is in idling in terms of cancelation. Otherwise we could end up waiting
forever in __io_uring_task_cancel() if the task has active iopoll
requests that need cancelation.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we enter with requests pending and performm cancelations, we'll have
a different inflight count before and after calling prepare_to_wait().
This causes the loop to restart. If we actually ended up canceling
everything, or everything completed in-between, then we'll break out
of the loop without calling finish_wait() on the waitqueue. This can
trigger a warning on exit_signals(), as we leave the task state in
TASK_UNINTERRUPTIBLE.
Put a finish_wait() after the loop to catch that case.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Right now io_flush_timeouts() checks if the current number of events
is equal to ->timeout.target_seq, but this will miss some timeouts if
there have been more than 1 event added since the last time they were
flushed (possible in io_submit_flush_completions(), for example). Fix
it by recording the last sequence at which timeouts were flushed so
that the number of events seen can be compared to the number of events
needed without overflow.
Signed-off-by: Marcelo Diop-Gonzalez <marcelo827@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: CPU: 0 PID: 8494 at fs/io_uring.c:8717
io_ring_ctx_wait_and_kill+0x4f2/0x600 fs/io_uring.c:8717
Call Trace:
io_uring_release+0x3e/0x50 fs/io_uring.c:8759
__fput+0x283/0x920 fs/file_table.c:280
task_work_run+0xdd/0x190 kernel/task_work.c:140
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
entry_SYSCALL_64_after_hwframe+0x44/0xa9
failed io_uring_install_fd() is a special case, we don't do
io_ring_ctx_wait_and_kill() directly but defer it to fput, though still
need to io_disable_sqo_submit() before.
note: it doesn't fix any real problem, just a warning. That's because
sqring won't be available to the userspace in this case and so SQPOLL
won't submit anything.
Reported-by: syzbot+9c9c35374c0ecac06516@syzkaller.appspotmail.com
Fixes: d9d05217cb ("io_uring: stop SQPOLL submit on creator's death")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
general protection fault, probably for non-canonical address
0xdffffc0000000022: 0000 [#1] KASAN: null-ptr-deref
in range [0x0000000000000110-0x0000000000000117]
RIP: 0010:io_ring_set_wakeup_flag fs/io_uring.c:6929 [inline]
RIP: 0010:io_disable_sqo_submit+0xdb/0x130 fs/io_uring.c:8891
Call Trace:
io_uring_create fs/io_uring.c:9711 [inline]
io_uring_setup+0x12b1/0x38e0 fs/io_uring.c:9739
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
io_disable_sqo_submit() might be called before user rings were
allocated, don't do io_ring_set_wakeup_flag() in those cases.
Reported-by: syzbot+ab412638aeb652ded540@syzkaller.appspotmail.com
Fixes: d9d05217cb ("io_uring: stop SQPOLL submit on creator's death")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In rare cases a task may be exiting while io_ring_exit_work() trying to
cancel/wait its requests. It's ok for __io_sq_thread_acquire_mm()
because of SQPOLL check, but is not for __io_sq_thread_acquire_files().
Play safe and fail for both of them.
Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__io_req_task_submit() run by task_work can set mm and files, but
io_sq_thread() in some cases, and because __io_sq_thread_acquire_mm()
and __io_sq_thread_acquire_files() do a simple current->mm/files check
it may end up submitting IO with mm/files of another task.
We also need to drop it after in the end to drop potentially grabbed
references to them.
Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When the creator of SQPOLL io_uring dies (i.e. sqo_task), we don't want
its internals like ->files and ->mm to be poked by the SQPOLL task, it
have never been nice and recently got racy. That can happen when the
owner undergoes destruction and SQPOLL tasks tries to submit new
requests in parallel, and so calls io_sq_thread_acquire*().
That patch halts SQPOLL submissions when sqo_task dies by introducing
sqo_dead flag. Once set, the SQPOLL task must not do any submission,
which is synchronised by uring_lock as well as the new flag.
The tricky part is to make sure that disabling always happens, that
means either the ring is discovered by creator's do_exit() -> cancel,
or if the final close() happens before it's done by the creator. The
last is guaranteed by the fact that for SQPOLL the creator task and only
it holds exactly one file note, so either it pins up to do_exit() or
removed by the creator on the final put in flush. (see comments in
uring_flush() around file->f_count == 2).
One more place that can trigger io_sq_thread_acquire_*() is
__io_req_task_submit(). Shoot off requests on sqo_dead there, even
though actually we don't need to. That's because cancellation of
sqo_task should wait for the request before going any further.
note 1: io_disable_sqo_submit() does io_ring_set_wakeup_flag() so the
caller would enter the ring to get an error, but it still doesn't
guarantee that the flag won't be cleared.
note 2: if final __userspace__ close happens not from the creator
task, the file note will pin the ring until the task dies.
Fixed: b1b6b5a30d ("kernel/io_uring: cancel io_uring before task works")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
files_cancel() should cancel all relevant requests and drop file notes,
so we should never have file notes after that, including on-exit fput
and flush. Add a WARN_ONCE to be sure.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We expect io_rw_reissue() to take place only during submission with
uring_lock held. Add a lockdep annotation to check that invariant.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
waitqueue_active() needs smp_mb() to be in sync with waitqueues
modification, but we miss it in io_cqring_ev_posted*() apart from
cq_wait() case.
Take an smb_mb() out of wq_has_sleeper() making it waitqueue_active(),
and place it a few lines before, so it can synchronise other
waitqueue_active() as well.
The patch doesn't add any additional overhead, so even if there are
no problems currently, it's just safer to have it this way.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
CPU0 CPU1
---- ----
lock(&new->fa_lock);
local_irq_disable();
lock(&ctx->completion_lock);
lock(&new->fa_lock);
<Interrupt>
lock(&ctx->completion_lock);
*** DEADLOCK ***
Move kill_fasync() out of io_commit_cqring() to io_cqring_ev_posted(),
so it doesn't hold completion_lock while doing it. That saves from the
reported deadlock, and it's just nice to shorten the locking time and
untangle nested locks (compl_lock -> wq_head::lock).
Reported-by: syzbot+91ca3f25bd7f795f019c@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make sure io_iopoll_complete() tries to wake up eventfd, which currently
is skipped together with io_cqring_ev_posted() for non-SQPOLL IOPOLL.
Add an iopoll version of io_cqring_ev_posted(), duplicates a bit of
code, but they actually use different sets of wait queues may be for
better.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
alloc_fixed_file_ref_node() currently returns an ERR_PTR on failure.
io_sqe_files_unregister() expects it to return NULL and since it can only
return -ENOMEM, it makes more sense to change alloc_fixed_file_ref_node()
to behave that way.
Fixes: 1ffc54220c ("io_uring: fix io_sqe_files_unregister() hangs")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Fix follow warning:
fs/io_uring.c:1523:22: warning: variable ‘id’ set but not used
[-Wunused-but-set-variable]
struct io_identity *id;
^~
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
While io_ring_exit_work() is running new requests of all sorts may be
issued, so it should do a bit more to cancel them, otherwise they may
just get stuck. e.g. in io-wq, in poll lists, etc.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring fds marked O_CLOEXEC and we explicitly cancel all requests
before going through exec, so we don't want to leave task's file
references to not our anymore io_uring instances.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IOPOLL skips completion locking but keeps it under uring_lock, thus
io_cqring_overflow_flush() and so io_cqring_events() need additional
locking with uring_lock in some cases for IOPOLL.
Remove __io_cqring_overflow_flush() from io_cqring_events(), introduce a
wrapper around flush doing needed synchronisation and call it by hand.
Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_req_task_submit() might be called for IOPOLL, do the fail path under
uring_lock to comply with IOPOLL synchronisation based solely on it.
Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_sqe_files_unregister() uninterruptibly waits for enqueued ref nodes,
however requests keeping them may never complete, e.g. because of some
userspace dependency. Make sure it's interruptible otherwise it would
hang forever.
Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Setting a new reference node to a file data is not trivial, don't repeat
it, add and use a helper.
Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we COW the identity, we assume that ->mm never changes. But this
isn't true of multiple processes end up sharing the ring. Hence treat
id->mm like like any other process compontent when it comes to the
identity mapping. This is pretty trivial, just moving the existing grab
into io_grab_identity(), and including a check for the match.
Cc: stable@vger.kernel.org # 5.10
Fixes: 1e6fa5216a ("io_uring: COW io_identity on mismatch")
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>:
Tested-by: Christian Brauner <christian.brauner@ubuntu.com>:
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_iopoll_complete() does not hold completion_lock to complete polled io,
so in io_wq_submit_work(), we can not call io_req_complete() directly, to
complete polled io, otherwise there maybe concurrent access to cqring,
defer_list, etc, which is not safe. Commit dad1b1242f ("io_uring: always
let io_iopoll_complete() complete polled io") has fixed this issue, but
Pavel reported that IOPOLL apart from rw can do buf reg/unreg requests(
IORING_OP_PROVIDE_BUFFERS or IORING_OP_REMOVE_BUFFERS), so the fix is not
good.
Given that io_iopoll_complete() is always called under uring_lock, so here
for polled io, we can also get uring_lock to fix this issue.
Fixes: dad1b1242f ("io_uring: always let io_iopoll_complete() complete polled io")
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: don't deref 'req' after completing it']
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Once we created a file for current context during setup, we should not
call io_ring_ctx_wait_and_kill() directly as it'll be done by fput(file)
Cc: stable@vger.kernel.org # 5.10
Reported-by: syzbot+c9937dfb2303a5f18640@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: fix unused 'ret' for !CONFIG_UNIX]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Get rid of TASK_UNINTERRUPTIBLE and waiting with finish_wait before
going for next iteration in __io_uring_task_cancel(), because
__io_uring_files_cancel() doesn't expect that sheduling is disallowed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Might happen that __io_uring_cancel_task_requests() cancels nothing but
there are task_works pending. We need to always run them.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Before IORING_SETUP_ATTACH_WQ, we could just cancel everything on the
io-wq when exiting. But that's not the case if they are shared, so
cancel for the specific ctx instead.
Cc: stable@vger.kernel.org
Fixes: 24369c2e3b ("io_uring: add io-wq workqueue sharing")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The purpose of io_uring_cancel_files() is to wait for all requests
matching ->files to go/be cancelled. We should first drop files of a
request in io_req_drop_files() and only then make it undiscoverable for
io_uring_cancel_files.
First drop, then delete from list. It's ok to leave req->id->files
dangling, because it's not dereferenced by cancellation code, only
compared against. It would potentially go to sleep and be awaken by
following in io_req_drop_files() wake_up().
Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We don't need to take uring_lock for SQPOLL|IOPOLL to do
io_cqring_overflow_flush() when cq_overflow_list is empty, remove it
from the hot path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is only one user of it and the name is misleading, get rid of it
by inlining. By the way make overflow_flush's return value deduction
simpler.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper which calculates number of events in CQ. Handcoded version
of it in io_cqring_overflow_flush() is not the clearest thing, so it
makes it slightly more readable.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
list_empty_careful() is not racy only if some conditions are met, i.e.
no re-adds after del_init. io_cqring_overflow_flush() does list_move(),
so it's actually racy.
Remove those checks, we have ->cq_check_overflow for the fast path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring_cancel_task_requests() doesn't imply that the ring is going
away, it may continue to work well after that. The problem is that it
sets ->cq_overflow_flushed effectively disabling the CQ overflow feature
Split setting cq_overflow_flushed from flush, and do the first one only
on exit. It's ok in terms of cancellations because there is a
io_uring->in_idle check in __io_cqring_fill_event().
It also fixes a race with setting ->cq_overflow_flushed in
io_uring_cancel_task_requests, whuch's is not atomic and a part of a
bitmask with other flags. Though, the only other flag that's not set
during init is drain_next, so it's not as bad for sane architectures.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The kernel doesn't seem to have clear rules around this, but various
spots are using the mmap_sem to serialize access to modifying the
locked_vm count. Play it safe and lock the mm for write when accounting
or unaccounting locked memory.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Ensure that the return value of __sys_shutdown_sock() is used to
potentially break links to the request, if we fail.
Fixes: 36f4fa6886 ("io_uring: add support for shutdown(2)")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
"Another series of killing more code than what is being added, again
thanks to Christoph's relentless cleanups and tech debt tackling.
This contains:
- blk-iocost improvements (Baolin Wang)
- part0 iostat fix (Jeffle Xu)
- Disable iopoll for split bios (Jeffle Xu)
- block tracepoint cleanups (Christoph Hellwig)
- Merging of struct block_device and hd_struct (Christoph Hellwig)
- Rework/cleanup of how block device sizes are updated (Christoph
Hellwig)
- Simplification of gendisk lookup and removal of block device
aliasing (Christoph Hellwig)
- Block device ioctl cleanups (Christoph Hellwig)
- Removal of bdget()/blkdev_get() as exported API (Christoph Hellwig)
- Disk change rework, avoid ->revalidate_disk() (Christoph Hellwig)
- sbitmap improvements (Pavel Begunkov)
- Hybrid polling fix (Pavel Begunkov)
- bvec iteration improvements (Pavel Begunkov)
- Zone revalidation fixes (Damien Le Moal)
- blk-throttle limit fix (Yu Kuai)
- Various little fixes"
* tag 'for-5.11/block-2020-12-14' of git://git.kernel.dk/linux-block: (126 commits)
blk-mq: fix msec comment from micro to milli seconds
blk-mq: update arg in comment of blk_mq_map_queue
blk-mq: add helper allocating tagset->tags
Revert "block: Fix a lockdep complaint triggered by request queue flushing"
nvme-loop: use blk_mq_hctx_set_fq_lock_class to set loop's lock class
blk-mq: add new API of blk_mq_hctx_set_fq_lock_class
block: disable iopoll for split bio
block: Improve blk_revalidate_disk_zones() checks
sbitmap: simplify wrap check
sbitmap: replace CAS with atomic and
sbitmap: remove swap_lock
sbitmap: optimise sbitmap_deferred_clear()
blk-mq: skip hybrid polling if iopoll doesn't spin
blk-iocost: Factor out the base vrate change into a separate function
blk-iocost: Factor out the active iocgs' state check into a separate function
blk-iocost: Move the usage ratio calculation to the correct place
blk-iocost: Remove unnecessary advance declaration
blk-iocost: Fix some typos in comments
blktrace: fix up a kerneldoc comment
block: remove the request_queue to argument request based tracepoints
...
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Merge tag 'for-5.11/io_uring-2020-12-14' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
"Fairly light set of changes this time around, and mostly some bits
that were pushed out to 5.11 instead of 5.10, fixes/cleanups, and a
few features. In particular:
- Cleanups around iovec import (David Laight, Pavel)
- Add timeout support for io_uring_enter(2), which enables us to
clean up liburing and avoid a timeout sqe submission in the
completion path.
The big win here is that it allows setups that split SQ and CQ
handling into separate threads to avoid locking, as the CQ side
will no longer submit when timeouts are needed when waiting for
events (Hao Xu)
- Add support for socket shutdown, and renameat/unlinkat.
- SQPOLL cleanups and improvements (Xiaoguang Wang)
- Allow SQPOLL setups for CAP_SYS_NICE, and enable regular
(non-fixed) files to be used.
- Cancelation improvements (Pavel)
- Fixed file reference improvements (Pavel)
- IOPOLL related race fixes (Pavel)
- Lots of other little fixes and cleanups (mostly Pavel)"
* tag 'for-5.11/io_uring-2020-12-14' of git://git.kernel.dk/linux-block: (43 commits)
io_uring: fix io_cqring_events()'s noflush
io_uring: fix racy IOPOLL flush overflow
io_uring: fix racy IOPOLL completions
io_uring: always let io_iopoll_complete() complete polled io
io_uring: add timeout update
io_uring: restructure io_timeout_cancel()
io_uring: fix files cancellation
io_uring: use bottom half safe lock for fixed file data
io_uring: fix miscounting ios_left
io_uring: change submit file state invariant
io_uring: check kthread stopped flag when sq thread is unparked
io_uring: share fixed_file_refs b/w multiple rsrcs
io_uring: replace inflight_wait with tctx->wait
io_uring: don't take fs for recvmsg/sendmsg
io_uring: only wake up sq thread while current task is in io worker context
io_uring: don't acquire uring_lock twice
io_uring: initialize 'timeout' properly in io_sq_thread()
io_uring: refactor io_sq_thread() handling
io_uring: always batch cancel in *cancel_files()
io_uring: pass files into kill timeouts/poll
...
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Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block
Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe:
"This sits on top of of the core entry/exit and x86 entry branch from
the tip tree, which contains the generic and x86 parts of this work.
Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL.
With that done, we can get rid of JOBCTL_TASK_WORK from task_work and
signal.c, and also remove a deadlock work-around in io_uring around
knowing that signal based task_work waking is invoked with the sighand
wait queue head lock.
The motivation for this work is to decouple signal notify based
task_work, of which io_uring is a heavy user of, from sighand. The
sighand lock becomes a huge contention point, particularly for
threaded workloads where it's shared between threads. Even outside of
threaded applications it's slower than it needs to be.
Roman Gershman <romger@amazon.com> reported that his networked
workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU
after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all
spent hammering on the sighand lock, showing 57% of the CPU time there
[1].
There are further cleanups possible on top of this. One example is
TIF_PATCH_PENDING, where a patch already exists to use
TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more
consolidation, but the work stands on its own as well"
[1] https://github.com/axboe/liburing/issues/215
* tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits)
io_uring: remove 'twa_signal_ok' deadlock work-around
kernel: remove checking for TIF_NOTIFY_SIGNAL
signal: kill JOBCTL_TASK_WORK
io_uring: JOBCTL_TASK_WORK is no longer used by task_work
task_work: remove legacy TWA_SIGNAL path
sparc: add support for TIF_NOTIFY_SIGNAL
riscv: add support for TIF_NOTIFY_SIGNAL
nds32: add support for TIF_NOTIFY_SIGNAL
ia64: add support for TIF_NOTIFY_SIGNAL
h8300: add support for TIF_NOTIFY_SIGNAL
c6x: add support for TIF_NOTIFY_SIGNAL
alpha: add support for TIF_NOTIFY_SIGNAL
xtensa: add support for TIF_NOTIFY_SIGNAL
arm: add support for TIF_NOTIFY_SIGNAL
microblaze: add support for TIF_NOTIFY_SIGNAL
hexagon: add support for TIF_NOTIFY_SIGNAL
csky: add support for TIF_NOTIFY_SIGNAL
openrisc: add support for TIF_NOTIFY_SIGNAL
sh: add support for TIF_NOTIFY_SIGNAL
um: add support for TIF_NOTIFY_SIGNAL
...
Pull execve updates from Eric Biederman:
"This set of changes ultimately fixes the interaction of posix file
lock and exec. Fundamentally most of the change is just moving where
unshare_files is called during exec, and tweaking the users of
files_struct so that the count of files_struct is not unnecessarily
played with.
Along the way fcheck and related helpers were renamed to more
accurately reflect what they do.
There were also many other small changes that fell out, as this is the
first time in a long time much of this code has been touched.
Benchmarks haven't turned up any practical issues but Al Viro has
observed a possibility for a lot of pounding on task_lock. So I have
some changes in progress to convert put_files_struct to always rcu
free files_struct. That wasn't ready for the merge window so that will
have to wait until next time"
* 'exec-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
exec: Move io_uring_task_cancel after the point of no return
coredump: Document coredump code exclusively used by cell spufs
file: Remove get_files_struct
file: Rename __close_fd_get_file close_fd_get_file
file: Replace ksys_close with close_fd
file: Rename __close_fd to close_fd and remove the files parameter
file: Merge __alloc_fd into alloc_fd
file: In f_dupfd read RLIMIT_NOFILE once.
file: Merge __fd_install into fd_install
proc/fd: In fdinfo seq_show don't use get_files_struct
bpf/task_iter: In task_file_seq_get_next use task_lookup_next_fd_rcu
proc/fd: In proc_readfd_common use task_lookup_next_fd_rcu
file: Implement task_lookup_next_fd_rcu
kcmp: In get_file_raw_ptr use task_lookup_fd_rcu
proc/fd: In tid_fd_mode use task_lookup_fd_rcu
file: Implement task_lookup_fd_rcu
file: Rename fcheck lookup_fd_rcu
file: Replace fcheck_files with files_lookup_fd_rcu
file: Factor files_lookup_fd_locked out of fcheck_files
file: Rename __fcheck_files to files_lookup_fd_raw
...
Core:
- support "prefer busy polling" NAPI operation mode, where we defer softirq
for some time expecting applications to periodically busy poll
- AF_XDP: improve efficiency by more batching and hindering
the adjacency cache prefetcher
- af_packet: make packet_fanout.arr size configurable up to 64K
- tcp: optimize TCP zero copy receive in presence of partial or unaligned
reads making zero copy a performance win for much smaller messages
- XDP: add bulk APIs for returning / freeing frames
- sched: support fragmenting IP packets as they come out of conntrack
- net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs
BPF:
- BPF switch from crude rlimit-based to memcg-based memory accounting
- BPF type format information for kernel modules and related tracing
enhancements
- BPF implement task local storage for BPF LSM
- allow the FENTRY/FEXIT/RAW_TP tracing programs to use bpf_sk_storage
Protocols:
- mptcp: improve multiple xmit streams support, memory accounting and
many smaller improvements
- TLS: support CHACHA20-POLY1305 cipher
- seg6: add support for SRv6 End.DT4/DT6 behavior
- sctp: Implement RFC 6951: UDP Encapsulation of SCTP
- ppp_generic: add ability to bridge channels directly
- bridge: Connectivity Fault Management (CFM) support as is defined in
IEEE 802.1Q section 12.14.
Drivers:
- mlx5: make use of the new auxiliary bus to organize the driver internals
- mlx5: more accurate port TX timestamping support
- mlxsw:
- improve the efficiency of offloaded next hop updates by using
the new nexthop object API
- support blackhole nexthops
- support IEEE 802.1ad (Q-in-Q) bridging
- rtw88: major bluetooth co-existance improvements
- iwlwifi: support new 6 GHz frequency band
- ath11k: Fast Initial Link Setup (FILS)
- mt7915: dual band concurrent (DBDC) support
- net: ipa: add basic support for IPA v4.5
Refactor:
- a few pieces of in_interrupt() cleanup work from Sebastian Andrzej Siewior
- phy: add support for shared interrupts; get rid of multiple driver
APIs and have the drivers write a full IRQ handler, slight growth
of driver code should be compensated by the simpler API which
also allows shared IRQs
- add common code for handling netdev per-cpu counters
- move TX packet re-allocation from Ethernet switch tag drivers to
a central place
- improve efficiency and rename nla_strlcpy
- number of W=1 warning cleanups as we now catch those in a patchwork
build bot
Old code removal:
- wan: delete the DLCI / SDLA drivers
- wimax: move to staging
- wifi: remove old WDS wifi bridging support
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core:
- support "prefer busy polling" NAPI operation mode, where we defer
softirq for some time expecting applications to periodically busy
poll
- AF_XDP: improve efficiency by more batching and hindering the
adjacency cache prefetcher
- af_packet: make packet_fanout.arr size configurable up to 64K
- tcp: optimize TCP zero copy receive in presence of partial or
unaligned reads making zero copy a performance win for much smaller
messages
- XDP: add bulk APIs for returning / freeing frames
- sched: support fragmenting IP packets as they come out of conntrack
- net: allow virtual netdevs to forward UDP L4 and fraglist GSO skbs
BPF:
- BPF switch from crude rlimit-based to memcg-based memory accounting
- BPF type format information for kernel modules and related tracing
enhancements
- BPF implement task local storage for BPF LSM
- allow the FENTRY/FEXIT/RAW_TP tracing programs to use
bpf_sk_storage
Protocols:
- mptcp: improve multiple xmit streams support, memory accounting and
many smaller improvements
- TLS: support CHACHA20-POLY1305 cipher
- seg6: add support for SRv6 End.DT4/DT6 behavior
- sctp: Implement RFC 6951: UDP Encapsulation of SCTP
- ppp_generic: add ability to bridge channels directly
- bridge: Connectivity Fault Management (CFM) support as is defined
in IEEE 802.1Q section 12.14.
Drivers:
- mlx5: make use of the new auxiliary bus to organize the driver
internals
- mlx5: more accurate port TX timestamping support
- mlxsw:
- improve the efficiency of offloaded next hop updates by using
the new nexthop object API
- support blackhole nexthops
- support IEEE 802.1ad (Q-in-Q) bridging
- rtw88: major bluetooth co-existance improvements
- iwlwifi: support new 6 GHz frequency band
- ath11k: Fast Initial Link Setup (FILS)
- mt7915: dual band concurrent (DBDC) support
- net: ipa: add basic support for IPA v4.5
Refactor:
- a few pieces of in_interrupt() cleanup work from Sebastian Andrzej
Siewior
- phy: add support for shared interrupts; get rid of multiple driver
APIs and have the drivers write a full IRQ handler, slight growth
of driver code should be compensated by the simpler API which also
allows shared IRQs
- add common code for handling netdev per-cpu counters
- move TX packet re-allocation from Ethernet switch tag drivers to a
central place
- improve efficiency and rename nla_strlcpy
- number of W=1 warning cleanups as we now catch those in a patchwork
build bot
Old code removal:
- wan: delete the DLCI / SDLA drivers
- wimax: move to staging
- wifi: remove old WDS wifi bridging support"
* tag 'net-next-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1922 commits)
net: hns3: fix expression that is currently always true
net: fix proc_fs init handling in af_packet and tls
nfc: pn533: convert comma to semicolon
af_vsock: Assign the vsock transport considering the vsock address flags
af_vsock: Set VMADDR_FLAG_TO_HOST flag on the receive path
vsock_addr: Check for supported flag values
vm_sockets: Add VMADDR_FLAG_TO_HOST vsock flag
vm_sockets: Add flags field in the vsock address data structure
net: Disable NETIF_F_HW_TLS_TX when HW_CSUM is disabled
tcp: Add logic to check for SYN w/ data in tcp_simple_retransmit
net: mscc: ocelot: install MAC addresses in .ndo_set_rx_mode from process context
nfc: s3fwrn5: Release the nfc firmware
net: vxget: clean up sparse warnings
mlxsw: spectrum_router: Use eXtended mezzanine to offload IPv4 router
mlxsw: spectrum: Set KVH XLT cache mode for Spectrum2/3
mlxsw: spectrum_router_xm: Introduce basic XM cache flushing
mlxsw: reg: Add Router LPM Cache Enable Register
mlxsw: reg: Add Router LPM Cache ML Delete Register
mlxsw: spectrum_router_xm: Implement L-value tracking for M-index
mlxsw: reg: Add XM Router M Table Register
...
Daniel Borkmann says:
====================
pull-request: bpf-next 2020-12-14
1) Expose bpf_sk_storage_*() helpers to iterator programs, from Florent Revest.
2) Add AF_XDP selftests based on veth devs to BPF selftests, from Weqaar Janjua.
3) Support for finding BTF based kernel attach targets through libbpf's
bpf_program__set_attach_target() API, from Andrii Nakryiko.
4) Permit pointers on stack for helper calls in the verifier, from Yonghong Song.
5) Fix overflows in hash map elem size after rlimit removal, from Eric Dumazet.
6) Get rid of direct invocation of llc in BPF selftests, from Andrew Delgadillo.
7) Fix xsk_recvmsg() to reorder socket state check before access, from Björn Töpel.
8) Add new libbpf API helper to retrieve ring buffer epoll fd, from Brendan Jackman.
9) Batch of minor BPF selftest improvements all over the place, from Florian Lehner,
KP Singh, Jiri Olsa and various others.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (31 commits)
selftests/bpf: Add a test for ptr_to_map_value on stack for helper access
bpf: Permits pointers on stack for helper calls
libbpf: Expose libbpf ring_buffer epoll_fd
selftests/bpf: Add set_attach_target() API selftest for module target
libbpf: Support modules in bpf_program__set_attach_target() API
selftests/bpf: Silence ima_setup.sh when not running in verbose mode.
selftests/bpf: Drop the need for LLVM's llc
selftests/bpf: fix bpf_testmod.ko recompilation logic
samples/bpf: Fix possible hang in xdpsock with multiple threads
selftests/bpf: Make selftest compilation work on clang 11
selftests/bpf: Xsk selftests - adding xdpxceiver to .gitignore
selftests/bpf: Drop tcp-{client,server}.py from Makefile
selftests/bpf: Xsk selftests - Bi-directional Sockets - SKB, DRV
selftests/bpf: Xsk selftests - Socket Teardown - SKB, DRV
selftests/bpf: Xsk selftests - DRV POLL, NOPOLL
selftests/bpf: Xsk selftests - SKB POLL, NOPOLL
selftests/bpf: Xsk selftests framework
bpf: Only provide bpf_sock_from_file with CONFIG_NET
bpf: Return -ENOTSUPP when attaching to non-kernel BTF
xsk: Validate socket state in xsk_recvmsg, prior touching socket members
...
====================
Link: https://lore.kernel.org/r/20201214214316.20642-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The TIF_NOTIFY_SIGNAL based implementation of TWA_SIGNAL is always safe
to use, regardless of context, as we won't be recursing into the signal
lock. So now that all archs are using that, we can drop this deadlock
work-around as it's always safe to use TWA_SIGNAL.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
