The kernel test robot complains about __io_remove_buffers().
io_uring/kbuf.c:221 __io_remove_buffers() warn: variable dereferenced
before check 'bl->buf_ring' (see line 219)
That check is not needed as ->buf_ring will always be set, so we can
remove it and so silence the warning.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9a632bbf749d9d911e605255652ce08d18e7d2c6.1681210788.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring/io_uring.c:432 io_prep_async_work() error: we previously
assumed 'req->file' could be null (see line 425).
Even though it's a false positive as there will not be REQ_F_ISREG set
without a file, let's add a simple check to make the kernel test robot
happy. We don't care about performance here, but assumingly it'll be
optimised out by the compiler.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/a6cfbe92c74b789c0b4f046f7f98d19b1ca2e5b7.1681210788.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We know now what the completion context is for the uring_cmd completion
handling, so use that to have io_req_task_complete() decide what the
best way to complete the request is. This allows batching of the posted
completions if we have multiple pending, rather than always doing them
one-by-one.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-6.3-2023-04-06' of git://git.kernel.dk/linux
Pull io_uring fixes from Jens Axboe:
"Just two minor fixes for provided buffers - one where we could
potentially leak a buffer, and one where the returned values was
off-by-one in some cases"
* tag 'io_uring-6.3-2023-04-06' of git://git.kernel.dk/linux:
io_uring: fix memory leak when removing provided buffers
io_uring: fix return value when removing provided buffers
Chains of memory accesses are never good for performance.
The req->task->io_uring->in_cancel in io_req_local_work_add() is there
so that when a task is exiting via io_uring_try_cancel_requests() and
starts waiting for completions, it gets woken up by every new task_work
item queued.
Do a little trick by announcing waiting in io_uring_try_cancel_requests(),
making io_req_local_work_add() wake us up. We also need to check for
deferred tw items after prepare_to_wait(TASK_INTERRUPTIBLE);
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fb11597e9bbcb365901824f8c5c2cf0d6ee100d0.1680782017.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Every task_work will try to wake the task to be executed, which causes
excessive scheduling and additional overhead. For some tw it's
justified, but others won't do much but post a single CQE.
When a task waits for multiple cqes, every such task_work will wake it
up. Instead, the task may give a hint about how many cqes it waits for,
io_req_local_work_add() will compare against it and skip wake ups
if #cqes + #tw is not enough to satisfy the waiting condition. Task_work
that uses the optimisation should be simple enough and never post more
than one CQE. It's also ignored for non DEFER_TASKRUN rings.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d2b77e99d1e86624d8a69f7037d764b739dcd225.1680782017.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We currently pin the ctx for io_req_local_work_add() with
percpu_ref_get/put, which implies two rcu_read_lock/unlock pairs and some
extra overhead on top in the fast path. Replace it with a pure rcu read
and let io_ring_exit_work() synchronise against it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cbdfcb6b232627f30e9e50ef91f13c4f05910247.1680782017.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rather than check this in the fast path issue, it makes more sense to
just assign the copy of the data when we're setting it up anyway. This
makes the code a bit cleaner, and removes the need for this check in
the issue path.
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct delayed_work rsrc_put_work was previously used to offload node
freeing because io_rsrc_node_ref_zero() was previously called by RCU in
the IRQ context. Now, as percpu refcounting is gone, we can do it
eagerly at the spot without pushing it to a worker.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/13fb1aac1e8d068ad8fd4a0c6d0d157ab61b90c0.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Every io_rsrc_node keeps a list of items to put, and all entries are
kmalloc()'ed. However, it's quite often to queue up only one entry per
node, so let's add an inline entry there to avoid extra allocations.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c482c1c652c45c85ac52e67c974bc758a50fed5f.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We have too many "rsrc" around which makes the name of struct
io_rsrc_node::rsrc_list confusing. The field is responsible for keeping
a list of files or buffers, so call it item_list and add comments
around.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3e34d4dfc1fdbb6b520f904ee6187c2ccf680efe.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We use ->rsrc_ref_lock spinlock to protect ->rsrc_ref_list in
io_rsrc_node_ref_zero(). Now we removed pcpu refcounting, which means
io_rsrc_node_ref_zero() is not executed from the irq context as an RCU
callback anymore, and we also put it under ->uring_lock.
io_rsrc_node_switch(), which queues up nodes into the list, is also
protected by ->uring_lock, so we can safely get rid of ->rsrc_ref_lock.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6b60af883c263551190b526a55ff2c9d5ae07141.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently, for nodes we have an atomic counter and some cached
(non-atomic) refs protected by uring_lock. Let's put all ref
manipulations under uring_lock and get rid of the atomic part.
It's free as in all cases we care about we already hold the lock.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/25b142feed7d831008257d90c8b17c0115d4fc15.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_free_req() is not often used but nevertheless problematic as there is
no way to know the current context, it may be used from the submission
path or even by an irq handler. Push it to a fresh context using
task_work.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3a92fe80bb068757e51aaa0b105cfbe8f5dfee9e.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We cache refs of the current node (i.e. ctx->rsrc_node) in
ctx->rsrc_cached_refs. We'll be moving away from atomics, so move the
cached refs in struct io_rsrc_node for now. It's a prep patch and
shouldn't change anything in practise.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9edc3669c1d71b06c2dca78b2b2b8bb9292738b9.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
One problem with the current rsrc infra is that often updates will
generates lots of rsrc nodes, each carry pcpu refs. That takes quite a
lot of memory, especially if there is a stall, and takes lots of CPU
cycles. Only pcpu allocations takes >50 of CPU with a naive benchmark
updating files in a loop.
Replace pcpu refs with normal refcounting. There is already a hot path
avoiding atomics / refs, but following patches will further improve it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e9ed8a9457b331a26555ff9443afc64cdaab7247.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We already do this manually for the !SQPOLL case, do it in general and
we can also dump the ugly min3() in io_submit_sqes().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It has nothing to do with the SQE at this point, it's a request
submission. While in there, get rid of the 'force_nonblock' argument
which is also dead, as we only pass in true.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
For task works we're passing around a bool pointer for whether the
current ring is locked or not, let's wrap it in a structure, that
will make it more opaque preventing abuse and will also help us
to pass more info in the future if needed.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1ecec9483d58696e248d1bfd52cf62b04442df1d.1679931367.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Before cond_resched()'ing in handle_tw_list() we also drop the current
ring context, and so the next loop iteration will need to pick/pin a new
context and do trylock.
The chunk removed by this patch was intended to be an optimisation
covering exactly this case, i.e. retaking the lock after reschedule, but
in reality it's skipped for the first iteration after resched as
described and will keep hammering the lock if it's contended.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1ecec9483d58696e248d1bfd52cf62b04442df1d.1679931367.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since the move to PF_IO_WORKER, we don't juggle memory context manually
anymore. Remove that outdated part of the comment for __io_worker_idle().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since commit 0654b05e7e65 ("io_uring: One wqe per wq"), we have just a
single io_wqe instance embedded per io_wq. Drop the extra structure in
favor of accessing struct io_wq directly, cleaning up quite a bit of
dereferences and backpointers.
No functional changes intended. Tested with liburing's testsuite
and mmtests performance microbenchmarks. I didn't observe any
performance regressions.
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230322011628.23359-2-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since we now have a single io_wqe per io_wq instead of per-node, and in
preparation to its removal, move the accounting into the parent
structure.
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230322011628.23359-2-krisman@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
On at least parisc, we have strict requirements on how we virtually map
an address that is shared between the application and the kernel. On
these platforms, IOU_PBUF_RING_MMAP should be used when setting up a
shared ring buffer for provided buffers. If the application is mapping
these pages and asking the kernel to pin+map them as well, then we have
no control over what virtual address we get in the kernel.
For that case, do a sanity check if SHM_COLOUR is defined, and disallow
the mapping request. The application must fall back to using
IOU_PBUF_RING_MMAP for this case, and liburing will do that transparently
with the set of helpers that it has.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add support for KASAN in the alloc_caches (apoll and netmsg_cache).
Thus, if something touches the unused caches, it will raise a KASAN
warning/exception.
It poisons the object when the object is put to the cache, and unpoisons
it when the object is gotten or freed.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230223164353.2839177-2-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Having cache entries linked using the hlist format brings no benefit, and
also requires an unnecessary extra pointer address per cache entry.
Use the internal io_wq_work_node single-linked list for the internal
alloc caches (async_msghdr and async_poll)
This is required to be able to use KASAN on cache entries, since we do
not need to touch unused (and poisoned) cache entries when adding more
entries to the list.
Suggested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230223164353.2839177-2-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Right now io_wq allocates one io_wqe per NUMA node. As io_wq is now
bound to a task, the task basically uses only the NUMA local io_wqe, and
almost never changes NUMA nodes, thus, the other wqes are mostly
unused.
Allocate just one io_wqe embedded into io_wq, and uses all possible cpus
(cpu_possible_mask) in the io_wqe->cpumask.
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230310201107.4020580-1-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The ring mapped provided buffer rings rely on the application allocating
the memory for the ring, and then the kernel will map it. This generally
works fine, but runs into issues on some architectures where we need
to be able to ensure that the kernel and application virtual address for
the ring play nicely together. This at least impacts architectures that
set SHM_COLOUR, but potentially also anyone setting SHMLBA.
To use this variant of ring provided buffers, the application need not
allocate any memory for the ring. Instead the kernel will do so, and
the allocation must subsequently call mmap(2) on the ring with the
offset set to:
IORING_OFF_PBUF_RING | (bgid << IORING_OFF_PBUF_SHIFT)
to get a virtual address for the buffer ring. Normally the application
would allocate a suitable piece of memory (and correctly aligned) and
simply pass that in via io_uring_buf_reg.ring_addr and the kernel would
map it.
Outside of the setup differences, the kernel allocate + user mapped
provided buffer ring works exactly the same.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for allowing flags to be set for registration, rename
the padding and use it for that.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rather than rely on checking buffer_list->buf_pages or ->buf_nr_pages,
add a separate member that tracks if this is a ring mapped provided
buffer list or not.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for allowing the kernel to allocate the provided buffer
rings and have the application mmap it instead, abstract out the
current method of pinning and mapping the user allocated ring.
No functional changes intended in this patch.
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some architectures have memory cache aliasing requirements (e.g. parisc)
if memory is shared between userspace and kernel. This patch fixes the
kernel to return an aliased address when asked by userspace via mmap().
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring hashes writes to a given file/inode so that it can serialize
them. This is useful if the file system needs exclusive access to the
file to perform the write, as otherwise we end up with a ton of io-wq
threads trying to lock the inode at the same time. This can cause
excessive system time.
But if the file system has flagged that it supports parallel O_DIRECT
writes, then there's no need to serialize the writes. Check for that
through FMODE_DIO_PARALLEL_WRITE and don't hash it if we don't need to.
In a basic test of 8 threads writing to a file on XFS on a gen2 Optane,
with each thread writing in 4k chunks, it improves performance from
~1350K IOPS (or ~5290MiB/sec) to ~1410K IOPS (or ~5500MiB/sec).
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When removing provided buffers, io_buffer structs are not being disposed
of, leading to a memory leak. They can't be freed individually, because
they are allocated in page-sized groups. They need to be added to some
free list instead, such as io_buffers_cache. All callers already hold
the lock protecting it, apart from when destroying buffers, so had to
extend the lock there.
Fixes: cc3cec8367 ("io_uring: speedup provided buffer handling")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When a request to remove buffers is submitted, and the given number to be
removed is larger than available in the specified buffer group, the
resulting CQE result will be the number of removed buffers + 1, which is
1 more than it should be.
Previously, the head was part of the list and it got removed after the
loop, so the increment was needed. Now, the head is not an element of
the list, so the increment shouldn't be there anymore.
Fixes: dbc7d452e7 ("io_uring: manage provided buffers strictly ordered")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Link: https://lore.kernel.org/r/20230401195039.404909-2-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-6.3-2023-03-30' of git://git.kernel.dk/linux
Pull io_uring fixes from Jens Axboe:
- Fix a regression with the poll retry, introduced in this merge window
(me)
- Fix a regression with the alloc cache not decrementing the member
count on removal. Also a regression from this merge window (Pavel)
- Fix race around rsrc node grabbing (Pavel)
* tag 'io_uring-6.3-2023-03-30' of git://git.kernel.dk/linux:
io_uring: fix poll/netmsg alloc caches
io_uring/rsrc: fix rogue rsrc node grabbing
io_uring/poll: clear single/double poll flags on poll arming
Conflicts:
drivers/net/ethernet/mediatek/mtk_ppe.c
3fbe4d8c0e ("net: ethernet: mtk_eth_soc: ppe: add support for flow accounting")
924531326e ("net: ethernet: mtk_eth_soc: add missing ppe cache flush when deleting a flow")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These just return the address and length of the current iovec segment
in the iterator. Convert existing iov_iter_iovec() users to use them
instead of getting a copy of the current vec.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This returns a pointer to the current iovec entry in the iterator. Only
useful with ITER_IOVEC right now, but it prepares us to treat ITER_UBUF
and ITER_IOVEC identically for the first segment.
Rename struct iov_iter->iov to iov_iter->__iov to find any potentially
troublesome spots, and also to prevent anyone from adding new code that
accesses iter->iov directly.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We increase cache->nr_cached when we free into the cache but don't
decrease when we take from it, so in some time we'll get an empty
cache with cache->nr_cached larger than IO_ALLOC_CACHE_MAX, that fails
io_alloc_cache_put() and effectively disables caching.
Fixes: 9b797a37c4 ("io_uring: add abstraction around apoll cache")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unless we have at least one entry queued, then don't call into
io_poll_remove_entries(). Normally this isn't possible, but if we
retry poll then we can have ->nr_entries cleared again as we're
setting it up. If this happens for a poll retry, then we'll still have
at least REQ_F_SINGLE_POLL set. io_poll_remove_entries() then thinks
it has entries to remove.
Clear REQ_F_SINGLE_POLL and REQ_F_DOUBLE_POLL unconditionally when
arming a poll request.
Fixes: c16bda3759 ("io_uring/poll: allow some retries for poll triggering spuriously")
Cc: stable@vger.kernel.org
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'block-6.3-2023-03-24' of git://git.kernel.dk/linux
Pull block fixes from Jens Axboe:
- NVMe pull request via Christoph:
- Send Identify with CNS 06h only to I/O controllers (Martin
George)
- Fix nvme_tcp_term_pdu to match spec (Caleb Sander)
- Pass in issue_flags for uring_cmd, so the end_io handlers don't need
to assume what the right context is (me)
- Fix for ublk, marking it as LIVE before adding it to avoid races on
the initial IO (Ming)
* tag 'block-6.3-2023-03-24' of git://git.kernel.dk/linux:
nvme-tcp: fix nvme_tcp_term_pdu to match spec
nvme: send Identify with CNS 06h only to I/O controllers
block/io_uring: pass in issue_flags for uring_cmd task_work handling
block: ublk_drv: mark device as LIVE before adding disk
When fixed files are unregistered, file_alloc_end and alloc_hint
are not cleared. This can later cause a NULL pointer dereference in
io_file_bitmap_get() if auto index selection is enabled via
IORING_FILE_INDEX_ALLOC:
[ 6.519129] BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
[ 6.541468] RIP: 0010:_find_next_zero_bit+0x1a/0x70
[...]
[ 6.560906] Call Trace:
[ 6.561322] <TASK>
[ 6.561672] io_file_bitmap_get+0x38/0x60
[ 6.562281] io_fixed_fd_install+0x63/0xb0
[ 6.562851] ? __pfx_io_socket+0x10/0x10
[ 6.563396] io_socket+0x93/0xf0
[ 6.563855] ? __pfx_io_socket+0x10/0x10
[ 6.564411] io_issue_sqe+0x5b/0x3d0
[ 6.564914] io_submit_sqes+0x1de/0x650
[ 6.565452] __do_sys_io_uring_enter+0x4fc/0xb20
[ 6.566083] ? __do_sys_io_uring_register+0x11e/0xd80
[ 6.566779] do_syscall_64+0x3c/0x90
[ 6.567247] entry_SYSCALL_64_after_hwframe+0x72/0xdc
[...]
To fix the issue, set file alloc range and alloc_hint to zero after
file tables are freed.
Cc: stable@vger.kernel.org
Fixes: 4278a0deb1 ("io_uring: defer alloc_hint update to io_file_bitmap_set()")
Signed-off-by: Savino Dicanosa <sd7.dev@pm.me>
[axboe: add explicit bitmap == NULL check as well]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since io_uring does nonblocking connect requests, if we do two repeated
ones without having a listener, the second will get -ECONNABORTED rather
than the expected -ECONNREFUSED. Treat -ECONNABORTED like a normal retry
condition if we're nonblocking, if we haven't already seen it.
Cc: stable@vger.kernel.org
Fixes: 3fb1bd6881 ("io_uring/net: handle -EINPROGRESS correct for IORING_OP_CONNECT")
Link: https://github.com/axboe/liburing/issues/828
Reported-by: Hui, Chunyang <sanqian.hcy@antgroup.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring_cmd_done() currently assumes that the uring_lock is held
when invoked, and while it generally is, this is not guaranteed.
Pass in the issue_flags associated with it, so that we have
IO_URING_F_UNLOCKED available to be able to lock the CQ ring
appropriately when completing events.
Cc: stable@vger.kernel.org
Fixes: ee692a21e9 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_uring provides the only way user space can poll completions, and that
always sets BLK_POLL_NOSLEEP. This effectively makes hybrid polling dead
code, so remove it and everything supporting it.
Hybrid polling was effectively killed off with 9650b453a3, "block:
ignore RWF_HIPRI hint for sync dio", but still potentially reachable
through io_uring until d729cf9acb, "io_uring: don't sleep when
polling for I/O", but hybrid polling probably should not have been
reachable through that async interface from the beginning.
Fixes: 9650b453a3 ("block: ignore RWF_HIPRI hint for sync dio")
Fixes: d729cf9acb ("io_uring: don't sleep when polling for I/O")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20230320194926.3353144-1-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| BUG: Bad page state in process kworker/u8:0 pfn:5c001
| page:00000000bfda61c8 refcount:0 mapcount:0 mapping:0000000000000000 index:0x20001 pfn:0x5c001
| head:0000000011409842 order:9 entire_mapcount:0 nr_pages_mapped:0 pincount:1
| anon flags: 0x3fffc00000b0004(uptodate|head|mappedtodisk|swapbacked|node=0|zone=0|lastcpupid=0xffff)
| raw: 03fffc0000000000 fffffc0000700001 ffffffff00700903 0000000100000000
| raw: 0000000000000200 0000000000000000 00000000ffffffff 0000000000000000
| head: 03fffc00000b0004 dead000000000100 dead000000000122 ffff00000a809dc1
| head: 0000000000020000 0000000000000000 00000000ffffffff 0000000000000000
| page dumped because: nonzero pincount
| CPU: 3 PID: 9 Comm: kworker/u8:0 Not tainted 6.3.0-rc2-00001-gc6811bf0cd87 #1
| Hardware name: linux,dummy-virt (DT)
| Workqueue: events_unbound io_ring_exit_work
| Call trace:
| dump_backtrace+0x13c/0x208
| show_stack+0x34/0x58
| dump_stack_lvl+0x150/0x1a8
| dump_stack+0x20/0x30
| bad_page+0xec/0x238
| free_tail_pages_check+0x280/0x350
| free_pcp_prepare+0x60c/0x830
| free_unref_page+0x50/0x498
| free_compound_page+0xcc/0x100
| free_transhuge_page+0x1f0/0x2b8
| destroy_large_folio+0x80/0xc8
| __folio_put+0xc4/0xf8
| gup_put_folio+0xd0/0x250
| unpin_user_page+0xcc/0x128
| io_buffer_unmap+0xec/0x2c0
| __io_sqe_buffers_unregister+0xa4/0x1e0
| io_ring_exit_work+0x68c/0x1188
| process_one_work+0x91c/0x1a58
| worker_thread+0x48c/0xe30
| kthread+0x278/0x2f0
| ret_from_fork+0x10/0x20
Mark reports an issue with the recent patches coalescing compound pages
while registering them in io_uring. The reason is that we try to drop
excessive references with folio_put_refs(), but pages were acquired
with pin_user_pages(), which has extra accounting and so should be put
down with matching unpin_user_pages() or at least gup_put_folio().
As a fix unpin_user_pages() all but first page instead, and let's figure
out a better API after.
Fixes: 57bebf807e ("io_uring/rsrc: optimise registered huge pages")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Tested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/10efd5507d6d1f05ea0f3c601830e08767e189bd.1678980230.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
msg_ring requests transferring files support auto index selection via
IORING_FILE_INDEX_ALLOC, however they don't return the selected index
to the target ring and there is no other good way for the userspace to
know where is the receieved file.
Return the index for allocated slots and 0 otherwise, which is
consistent with other fixed file installing requests.
Cc: stable@vger.kernel.org # v6.0+
Fixes: e6130eba8a ("io_uring: add support for passing fixed file descriptors")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://github.com/axboe/liburing/issues/809
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The initialization assignment of the variable ret is changed to 0, only
in 'goto fail;' Use the ret variable as the function return value.
Signed-off-by: Li zeming <zeming@nfschina.com>
Link: https://lore.kernel.org/r/20230317182538.3027-1-zeming@nfschina.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Users may specify a CPU where the sqpoll thread would run. This may
conflict with cpuset operations because of strict PF_NO_SETAFFINITY
requirement. That flag is unnecessary for polling "kernel" threads, see
the reasoning in commit 01e68ce08a ("io_uring/io-wq: stop setting
PF_NO_SETAFFINITY on io-wq workers"). Drop the flag on poll threads too.
Fixes: 01e68ce08a ("io_uring/io-wq: stop setting PF_NO_SETAFFINITY on io-wq workers")
Link: https://lore.kernel.org/all/20230314162559.pnyxdllzgw7jozgx@blackpad/
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Link: https://lore.kernel.org/r/20230314183332.25834-1-mkoutny@suse.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If io_uring.o is built with W=1, it triggers a warning:
io_uring/io_uring.c: In function ‘__io_submit_flush_completions’:
io_uring/io_uring.c:1502:40: warning: variable ‘prev’ set but not used [-Wunused-but-set-variable]
1502 | struct io_wq_work_node *node, *prev;
| ^~~~
which is due to the wq_list_for_each() iterator always keeping a 'prev'
variable. Most users need this to remove an entry from a list, for
example, but __io_submit_flush_completions() never does that.
Add a basic helper that doesn't track prev instead, and use that in
that function.
Reported-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It's possible for a file type to support uring commands, but not
pollable ones. Hence before issuing one of those, we should check
that it is supported and error out upfront if it isn't.
Cc: stable@vger.kernel.org
Fixes: 5756a3a7e7 ("io_uring: add iopoll infrastructure for io_uring_cmd")
Link: https://github.com/axboe/liburing/issues/816
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Every now and then reports come in that are puzzled on why changing
affinity on the io-wq workers fails with EINVAL. This happens because they
set PF_NO_SETAFFINITY as part of their creation, as io-wq organizes
workers into groups based on what CPU they are running on.
However, this is purely an optimization and not a functional requirement.
We can allow setting affinity, and just lazily update our worker to wqe
mappings. If a given io-wq thread times out, it normally exits if there's
no more work to do. The exception is if it's the last worker available.
For the timeout case, check the affinity of the worker against group mask
and exit even if it's the last worker. New workers should be created with
the right mask and in the right location.
Reported-by:Daniel Dao <dqminh@cloudflare.com>
Link: https://lore.kernel.org/io-uring/CA+wXwBQwgxB3_UphSny-yAP5b26meeOu1W4TwYVcD_+5gOhvPw@mail.gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 0091bfc817 ("io_uring/af_unix: defer registered
files gc to io_uring release") added one bit to struct sk_buff.
This structure is critical for networking, and we try very hard
to not add bloat on it, unless absolutely required.
For instance, we can use a specific destructor as a wrapper
around unix_destruct_scm(), to identify skbs that unix_gc()
has to special case.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Merge tag 'io_uring-6.3-2023-03-03' of git://git.kernel.dk/linux
Pull more io_uring updates from Jens Axboe:
"Here's a set of fixes/changes that didn't make the first cut, either
because they got queued before I sent the early merge request, or
fixes that came in afterwards. In detail:
- Don't set MSG_NOSIGNAL on recv/recvmsg opcodes, as AF_PACKET will
error out (David)
- Fix for spurious poll wakeups (me)
- Fix for a file leak for buffered reads in certain conditions
(Joseph)
- Don't allow registered buffers of mixed types (Pavel)
- Improve handling of huge pages for registered buffers (Pavel)
- Provided buffer ring size calculation fix (Wojciech)
- Minor cleanups (me)"
* tag 'io_uring-6.3-2023-03-03' of git://git.kernel.dk/linux:
io_uring/poll: don't pass in wake func to io_init_poll_iocb()
io_uring: fix fget leak when fs don't support nowait buffered read
io_uring/poll: allow some retries for poll triggering spuriously
io_uring: remove MSG_NOSIGNAL from recvmsg
io_uring/rsrc: always initialize 'folio' to NULL
io_uring/rsrc: optimise registered huge pages
io_uring/rsrc: optimise single entry advance
io_uring/rsrc: disallow multi-source reg buffers
io_uring: remove unused wq_list_merge
io_uring: fix size calculation when registering buf ring
io_uring/rsrc: fix a comment in io_import_fixed()
io_uring: rename 'in_idle' to 'in_cancel'
io_uring: consolidate the put_ref-and-return section of adding work
Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an
array of two words. It was then obfuscated by hiding the "2" behind two
macro expansions, with the reasoning being that maybe it gets extended
further some day.
That reasoning may have been valid at the time, but the last thing we
want to do is to extend the capability set any more. And the array of
values not only causes source code oddities (with loops to deal with
it), but also results in worse code generation. It's a lose-lose
situation.
So just change the 'u32[2]' into a 'u64' and be done with it.
We still have to deal with the fact that the user space interface is
designed around an array of these 32-bit values, but that was the case
before too, since the array layouts were different (ie user space
doesn't use an array of 32-bit values for individual capability masks,
but an array of 32-bit slices of multiple masks).
So that marshalling of data is actually simplified too, even if it does
remain somewhat obscure and odd.
This was all triggered by my reaction to the new "cap_isidentical()"
introduced recently. By just using a saner data structure, it went from
unsigned __capi;
CAP_FOR_EACH_U32(__capi) {
if (a.cap[__capi] != b.cap[__capi])
return false;
}
return true;
to just being
return a.val == b.val;
instead. Which is rather more obvious both to humans and to compilers.
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We only use one, and it's io_poll_wake(). Hardwire that in the initial
init, as well as in __io_queue_proc() if we're setting up for double
poll.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Heming reported a BUG when using io_uring doing link-cp on ocfs2. [1]
Do the following steps can reproduce this BUG:
mount -t ocfs2 /dev/vdc /mnt/ocfs2
cp testfile /mnt/ocfs2/
./link-cp /mnt/ocfs2/testfile /mnt/ocfs2/testfile.1
umount /mnt/ocfs2
Then umount will fail, and it outputs:
umount: /mnt/ocfs2: target is busy.
While tracing umount, it blames mnt_get_count() not return as expected.
Do a deep investigation for fget()/fput() on related code flow, I've
finally found that fget() leaks since ocfs2 doesn't support nowait
buffered read.
io_issue_sqe
|-io_assign_file // do fget() first
|-io_read
|-io_iter_do_read
|-ocfs2_file_read_iter // return -EOPNOTSUPP
|-kiocb_done
|-io_rw_done
|-__io_complete_rw_common // set REQ_F_REISSUE
|-io_resubmit_prep
|-io_req_prep_async // override req->file, leak happens
This was introduced by commit a196c78b54 in v5.18. Fix it by don't
re-assign req->file if it has already been assigned.
[1] https://lore.kernel.org/ocfs2-devel/ab580a75-91c8-d68a-3455-40361be1bfa8@linux.alibaba.com/T/#t
Fixes: a196c78b54 ("io_uring: assign non-fixed early for async work")
Cc: <stable@vger.kernel.org>
Reported-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Link: https://lore.kernel.org/r/20230228045459.13524-1-joseph.qi@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we get woken spuriously when polling and fail the operation with
-EAGAIN again, then we generally only allow polling again if data
had been transferred at some point. This is indicated with
REQ_F_PARTIAL_IO. However, if the spurious poll triggers when the socket
was originally empty, then we haven't transferred data yet and we will
fail the poll re-arm. This either punts the socket to io-wq if it's
blocking, or it fails the request with -EAGAIN if not. Neither condition
is desirable, as the former will slow things down, while the latter
will make the application confused.
We want to ensure that a repeated poll trigger doesn't lead to infinite
work making no progress, that's what the REQ_F_PARTIAL_IO check was
for. But it doesn't protect against a loop post the first receive, and
it's unnecessarily strict if we started out with an empty socket.
Add a somewhat random retry count, just to put an upper limit on the
potential number of retries that will be done. This should be high enough
that we won't really hit it in practice, unless something needs to be
aborted anyway.
Cc: stable@vger.kernel.org # v5.10+
Link: https://github.com/axboe/liburing/issues/364
Signed-off-by: Jens Axboe <axboe@kernel.dk>
MSG_NOSIGNAL is not applicable for the receiving side, SIGPIPE is
generated when trying to write to a "broken pipe". AF_PACKET's
packet_recvmsg() does enforce this, giving back EINVAL when MSG_NOSIGNAL
is set - making it unuseable in io_uring's recvmsg.
Remove MSG_NOSIGNAL from io_recvmsg_prep().
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: David Lamparter <equinox@diac24.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230224150123.128346-1-equinox@diac24.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Smatch complains that:
smatch warnings:
io_uring/rsrc.c:1262 io_sqe_buffer_register() error: uninitialized symbol 'folio'.
'folio' may be used uninitialized, which can happen if we end up with a
single page mapped. Ensure that we clear folio to NULL at the top so
it's always set.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202302241432.YML1CD5C-lkp@intel.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter". These filters provide users
with finer-grained control over DAMOS's actions. SeongJae has also done
some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series "mm:
support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with his
series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings. The previous BPF-based approach had
shortcomings. See "mm: In-kernel support for memory-deny-write-execute
(MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a per-node
basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage during
compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in ths
series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's series
"mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
"fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest of
the kernel in the series "Simplify the external interface for GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the series
"mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
When registering huge pages, internally io_uring will split them into
many PAGE_SIZE bvec entries. That's bad for performance as drivers need
to eventually dma-map the data and will do it individually for each bvec
entry. Coalesce huge pages into one large bvec.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Iterating within the first bvec entry should be essentially free, but we
use iov_iter_advance() for that, which shows up in benchmark profiles
taking up to 0.5% of CPU. Replace it with a hand coded version.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If two or more mappings go back to back to each other they can be passed
into io_uring to be registered as a single registered buffer. That would
even work if mappings came from different sources, e.g. it's possible to
mix in this way anon pages and pages from shmem or hugetlb. That is not
a problem but it'd rather be less prone if we forbid such mixing.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Using struct_size() to calculate the size of io_uring_buf_ring will sum
the size of the struct and of the bufs array. However, the struct's fields
are overlaid with the array making the calculated size larger than it
should be.
When registering a ring with N * PAGE_SIZE / sizeof(struct io_uring_buf)
entries, i.e. with fully filled pages, the calculated size will span one
more page than it should and io_uring will try to pin the following page.
Depending on how the application allocated the ring, it might succeed
using an unrelated page or fail returning EFAULT.
The size of the ring should be the product of ring_entries and the size
of io_uring_buf, i.e. the size of the bufs array only.
Fixes: c7fb19428d ("io_uring: add support for ring mapped supplied buffers")
Signed-off-by: Wojciech Lukowicz <wlukowicz01@gmail.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Link: https://lore.kernel.org/r/20230218184141.70891-1-wlukowicz01@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This better describes what it does - it's incremented when the task is
currently undergoing a cancelation operation, due to exiting or exec'ing.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We've got a few cases of this, move them to one section and just use
gotos to get there. Reduces the text section on both arm64 and x86-64,
using gcc-12.2.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.3/block-2023-02-16' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe updates via Christoph:
- Small improvements to the logging functionality (Amit Engel)
- Authentication cleanups (Hannes Reinecke)
- Cleanup and optimize the DMA mapping cod in the PCIe driver
(Keith Busch)
- Work around the command effects for Format NVM (Keith Busch)
- Misc cleanups (Keith Busch, Christoph Hellwig)
- Fix and cleanup freeing single sgl (Keith Busch)
- MD updates via Song:
- Fix a rare crash during the takeover process
- Don't update recovery_cp when curr_resync is ACTIVE
- Free writes_pending in md_stop
- Change active_io to percpu
- Updates to drbd, inching us closer to unifying the out-of-tree driver
with the in-tree one (Andreas, Christoph, Lars, Robert)
- BFQ update adding support for multi-actuator drives (Paolo, Federico,
Davide)
- Make brd compliant with REQ_NOWAIT (me)
- Fix for IOPOLL and queue entering, fixing stalled IO waiting on
timeouts (me)
- Fix for REQ_NOWAIT with multiple bios (me)
- Fix memory leak in blktrace cleanup (Greg)
- Clean up sbitmap and fix a potential hang (Kemeng)
- Clean up some bits in BFQ, and fix a bug in the request injection
(Kemeng)
- Clean up the request allocation and issue code, and fix some bugs
related to that (Kemeng)
- ublk updates and fixes:
- Add support for unprivileged ublk (Ming)
- Improve device deletion handling (Ming)
- Misc (Liu, Ziyang)
- s390 dasd fixes (Alexander, Qiheng)
- Improve utility of request caching and fixes (Anuj, Xiao)
- zoned cleanups (Pankaj)
- More constification for kobjs (Thomas)
- blk-iocost cleanups (Yu)
- Remove bio splitting from drivers that don't need it (Christoph)
- Switch blk-cgroups to use struct gendisk. Some of this is now
incomplete as select late reverts were done. (Christoph)
- Add bvec initialization helpers, and convert callers to use that
rather than open-coding it (Christoph)
- Misc fixes and cleanups (Jinke, Keith, Arnd, Bart, Li, Martin,
Matthew, Ulf, Zhong)
* tag 'for-6.3/block-2023-02-16' of git://git.kernel.dk/linux: (169 commits)
brd: use radix_tree_maybe_preload instead of radix_tree_preload
block: use proper return value from bio_failfast()
block: bio-integrity: Copy flags when bio_integrity_payload is cloned
block: Fix io statistics for cgroup in throttle path
brd: mark as nowait compatible
brd: check for REQ_NOWAIT and set correct page allocation mask
brd: return 0/-error from brd_insert_page()
block: sync mixed merged request's failfast with 1st bio's
Revert "blk-cgroup: pin the gendisk in struct blkcg_gq"
Revert "blk-cgroup: pass a gendisk to blkg_lookup"
Revert "blk-cgroup: delay blk-cgroup initialization until add_disk"
Revert "blk-cgroup: delay calling blkcg_exit_disk until disk_release"
Revert "blk-cgroup: move the cgroup information to struct gendisk"
nvme-pci: remove iod use_sgls
nvme-pci: fix freeing single sgl
block: ublk: check IO buffer based on flag need_get_data
s390/dasd: Fix potential memleak in dasd_eckd_init()
s390/dasd: sort out physical vs virtual pointers usage
block: Remove the ALLOC_CACHE_SLACK constant
block: make kobj_type structures constant
...
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Merge tag 'for-6.3/iter-ubuf-2023-02-16' of git://git.kernel.dk/linux
Pull io_uring ITER_UBUF conversion from Jens Axboe:
"Since we now have ITER_UBUF available, switch to using it for single
ranges as it's more efficient than ITER_IOVEC for that"
* tag 'for-6.3/iter-ubuf-2023-02-16' of git://git.kernel.dk/linux:
block: use iter_ubuf for single range
iov_iter: move iter_ubuf check inside restore WARN
io_uring: use iter_ubuf for single range imports
io_uring: switch network send/recv to ITER_UBUF
iov: add import_ubuf()
Add a new flag IORING_REGISTER_USE_REGISTERED_RING (set via the high bit
of the opcode) to treat the fd as a registered index rather than a file
descriptor.
This makes it possible for a library to open an io_uring, register the
ring fd, close the ring fd, and subsequently use the ring entirely via
registered index.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: https://lore.kernel.org/r/f2396369e638284586b069dbddffb8c992afba95.1676419314.git.josh@joshtriplett.org
[axboe: remove extra high bit clear]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fadvise and madvise both provide hints for caching or access pattern for
file and memory respectively. Skip them.
Fixes: 5bd2182d58 ("audit,io_uring,io-wq: add some basic audit support to io_uring")
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Link: https://lore.kernel.org/r/b5dfdcd541115c86dbc774aa9dd502c964849c5f.1675282642.git.rgb@redhat.com
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Just like for task_work, set the task mode to TASK_RUNNING before doing
any potential resume work. We're not holding any locks at this point,
but we may have already set the task state to TASK_INTERRUPTIBLE in
preparation for going to sleep waiting for events. Ensure that we set it
back to TASK_RUNNING if we have work to process, to avoid warnings on
calling blocking operations with !TASK_RUNNING.
Fixes: b5d3ae202f ("io_uring: handle TIF_NOTIFY_RESUME when checking for task_work")
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202302062208.24d3e563-oliver.sang@intel.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use the bvec_set_page helper to initialize a bvec.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230203150634.3199647-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some requests require being run async as they do not support
non-blocking. Instead of trying to issue these requests, getting -EAGAIN
and then queueing them for async issue, rather just force async upfront.
Add WARN_ON_ONCE to make sure surprising code paths do not come up,
however in those cases the bug would end up being a blocking
io_uring_enter(2) which should not be critical.
Signed-off-by: Dylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20230127135227.3646353-3-dylany@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If CONFIG_PREEMPT_NONE is set and the task_work chains are long, we
could be running into issues blocking others for too long. Add a
reschedule check in handle_tw_list(), and flush the ctx if we need to
reschedule.
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add a helper for putting refs from the target task context, rename
__io_put_task() and add a couple of comments around. Use the remote
version for __io_req_complete_post(), the local is only needed for
__io_submit_flush_completions().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3bf92ebd594769d8a5d648472a8e335f2031d542.1674484266.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Return an SQE from io_get_sqe() as a parameter and use the return value
to determine if it failed or not. This enables the compiler to compile out
the sqe NULL check when we know that the return SQE is valid.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9cceb11329240ea097dffef6bf0a675bca14cf42.1674484266.git.asml.silence@gmail.com
[axboe: remove bogus const modifier on return value]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This generates better code for me, avoiding an extra load on arm64, and
both call sites already have this variable available for easy passing.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Every io_uring request is represented by struct io_kiocb, which is
cached locally by io_uring (not SLAB/SLUB) in the list called
submit_state.freelist. This patch simply enabled KASAN for this free
list.
This list is initially created by KMEM_CACHE, but later, managed by
io_uring. This patch basically poisons the objects that are not used
(i.e., they are the free list), and unpoisons it when the object is
allocated/removed from the list.
Touching these poisoned objects while in the freelist will cause a KASAN
warning.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work()
for PF_IO_WORKER threads. They never return to usermode, hence never get
a chance to process any items that are marked by this flag. Most notably
this includes the final put of files, but also any throttling markers set
by block cgroups.
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the target ring is using IORING_SETUP_SINGLE_ISSUER and we're posting
a message from a different thread, then we need to ensure that the
fallback task_work that posts the CQE knwos about the flags passing as
well. If not we'll always be posting 0 as the flags.
Fixes: 3563d7ed58a5 ("io_uring/msg_ring: Pass custom flags to the cqe")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch removes some "cold" fields from `struct io_issue_def`.
The plan is to keep only highly used fields into `struct io_issue_def`, so,
it may be hot in the cache. The hot fields are basically all the bitfields
and the callback functions for .issue and .prep.
The other less frequently used fields are now located in a secondary and
cold struct, called `io_cold_def`.
This is the size for the structs:
Before: io_issue_def = 56 bytes
After: io_issue_def = 24 bytes; io_cold_def = 40 bytes
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20230112144411.2624698-2-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The current io_op_def struct is becoming huge and the name is a bit
generic.
The goal of this patch is to rename this struct to `io_issue_def`. This
struct will contain the hot functions associated with the issue code
path.
For now, this patch only renames the structure, and an upcoming patch
will break up the structure in two, moving the non-issue fields to a
secondary struct.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20230112144411.2624698-1-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_submit_flush_completions() may queue new requests for tw execution,
especially true for linked requests. Recheck the tw list for emptiness
after flushing completions.
Note that this doesn't really fix the commit referenced below, but it
does reinstate an optimization that existed before that got merged.
Fixes: f88262e60b ("io_uring: lockless task list")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6328acdbb5e60efc762b18003382de077e6e1367.1673887636.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Change the return type to void since it always return 0, and no need
to do the checking in syscall io_uring_enter.
Signed-off-by: Quanfa Fu <quanfafu@gmail.com>
Link: https://lore.kernel.org/r/20230115071519.554282-1-quanfafu@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We needed fake nodes in __io_run_local_work() and to avoid unecessary wake
ups while the task already running task_works, but we don't need them
anymore since wake ups are protected by cq_waiting, which is always
cleared by the time we're executing deferred task_work items.
Note that because of loose sync around cq_waiting clearing
io_req_local_work_add() may wake the task more than once, but that's
fine and should be rare to not hurt perf.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8839534891f0a2f1076e78554a31ea7e099f7de5.1673274244.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
With DEFER_TASKRUN only ctx->submitter_task might be waiting for CQEs,
we can use this to optimise io_cqring_wait(). Replace ->cq_wait
waitqueue with waking the task directly.
It works but misses an important optimisation covered by the following
patch, so this patch without follow ups might hurt performance.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/103d174d35d919d4cb0922d8a9c93a8f0c35f74a.1673274244.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Flush completions is done either from the submit syscall or by the
task_work, both are in the context of the submitter task, and when it
goes for a single threaded rings like implied by ->task_complete, there
won't be any waiters on ->cq_wait but the master task. That means that
there can be no tasks sleeping on cq_wait while we run
__io_submit_flush_completions() and so waking up can be skipped.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/60ad9768ec74435a0ddaa6eec0ffa7729474f69f.1673274244.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Even though io_poll_wq_wake()'s waitqueue_active reuses a barrier we do
for another waitqueue, it's not going to be the case in the future and
so we want to have a fast path for it when the ring has never been
polled.
Move poll_wq wake ups into __io_commit_cqring_flush() using a new flag
called ->poll_activated. The idea behind the flag is to set it when the
ring was polled for the first time. This requires additional sync to not
miss events, which is done here by using task_work for ->task_complete
rings, and by default enabling the flag for all other types of rings.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/060785e8e9137a920b232c0c7f575b131af19cac.1673274244.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch adds a new flag (IORING_MSG_RING_FLAGS_PASS) in the message
ring operations (IORING_OP_MSG_RING). This new flag enables the sender
to specify custom flags, which will be copied over to cqe->flags in the
receiving ring. These custom flags should be specified using the
sqe->file_index field.
This mechanism provides additional flexibility when sending messages
between rings.
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://lore.kernel.org/r/20230103160507.617416-1-leitao@debian.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Unlike the jiffy scheduling version, schedule_hrtimeout() jumps a few
functions before getting into schedule() even if there is no actual
timeout needed. Some tests showed that it takes up to 1% of CPU cycles.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/89f880574eceee6f4899783377ead234df7b3d04.1672916894.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
io_cqring_wait_schedule() is called after we started waiting on the cq
wq and set the state to TASK_INTERRUPTIBLE, for that reason we have to
constantly worry whether we has returned the state back to running or
not. Leave only quick checks in io_cqring_wait_schedule() and move the
rest including running task work to the callers. Note, we run tw in the
loop after the sched checks because of the fast path in the beginning of
the function.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/2814fabe75e2e019e7ca43ea07daa94564349805.1672916894.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Most places that want to run local tw explicitly and in advance check if
they are allowed to do so. Don't rely on a similar check in
__io_run_local_work(), leave it as a just-in-case warning and make sure
callers checks capabilities themselves.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/990fe0e8e70fd4d57e43625e5ce8fba584821d1a.1672916894.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Task work runners keep running until all queues tw items are exhausted.
It's also rare for defer tw to queue normal tw and vise versa. Taking it
into account, there is only a dim chance that further iterating the
io_cqring_wait() fast path will get us anything and so we can remove
the loop there.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1f9565726661266abaa5d921e97433c831759ecf.1672916894.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Drain requests all go through io_drain_req, which has a quick exit in case
there is nothing pending (ie the drain is not useful). In that case it can
run the issue the request immediately.
However for safety it queues it through task work.
The problem is that in this case the request is run asynchronously, but
the async work has not been prepared through io_req_prep_async.
This has not been a problem up to now, as the task work always would run
before returning to userspace, and so the user would not have a chance to
race with it.
However - with IORING_SETUP_DEFER_TASKRUN - this is no longer the case and
the work might be defered, giving userspace a chance to change data being
referred to in the request.
Instead _always_ prep_async for drain requests, which is simpler anyway
and removes this issue.
Cc: stable@vger.kernel.org
Fixes: c0e0d6ba25 ("io_uring: add IORING_SETUP_DEFER_TASKRUN")
Signed-off-by: Dylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20230127105911.2420061-1-dylany@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we're using ring provided buffers with multishot receive, and we end
up doing an io-wq based issue at some points that also needs to select
a buffer, we'll lose the initially assigned buffer group as
io_ring_buffer_select() correctly clears the buffer group list as the
issue isn't serialized by the ctx uring_lock. This is fine for normal
receives as the request puts the buffer and finishes, but for multishot,
we will re-arm and do further receives. On the next trigger for this
multishot receive, the receive will try and pick from a buffer group
whose value is the same as the buffer ID of the las receive. That is
obviously incorrect, and will result in a premature -ENOUFS error for
the receive even if we had available buffers in the correct group.
Cache the buffer group value at prep time, so we can restore it for
future receives. This only needs doing for the above mentioned case, but
just do it by default to keep it easier to read.
Cc: stable@vger.kernel.org
Fixes: b3fdea6ecb ("io_uring: multishot recv")
Fixes: 9bb66906f2 ("io_uring: support multishot in recvmsg")
Cc: Dylan Yudaken <dylany@meta.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A previous commit fixed a poll race that can occur, but it's only
applicable for multishot requests. For a multishot request, we can safely
ignore a spurious wakeup, as we never leave the waitqueue to begin with.
A blunt reissue of a multishot armed request can cause us to leak a
buffer, if they are ring provided. While this seems like a bug in itself,
it's not really defined behavior to reissue a multishot request directly.
It's less efficient to do so as well, and not required to rearm anything
like it is for singleshot poll requests.
Cc: stable@vger.kernel.org
Fixes: 6e5aedb932 ("io_uring/poll: attempt request issue after racy poll wakeup")
Reported-and-tested-by: Olivier Langlois <olivier@trillion01.com>
Link: https://github.com/axboe/liburing/issues/778
Signed-off-by: Jens Axboe <axboe@kernel.dk>
IORING_SETUP_R_DISABLED rings don't have the submitter task set, so
it's not always safe to use ->submitter_task. Disallow posting msg_ring
messaged to disabled rings. Also add task NULL check for loosy sync
around testing for IORING_SETUP_R_DISABLED.
Cc: stable@vger.kernel.org
Fixes: 6d043ee116 ("io_uring: do msg_ring in target task via tw")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is a couple of problems with queueing a tw in io_msg_ring_data()
for remote execution. First, once we queue it the target ring can
go away and so setting IORING_SQ_TASKRUN there is not safe. Secondly,
the userspace might not expect IORING_SQ_TASKRUN.
Extract a helper and uniformly use TWA_SIGNAL without TWA_SIGNAL_NO_IPI
tricks for now, just as it was done in the original patch.
Cc: stable@vger.kernel.org
Fixes: 6d043ee116 ("io_uring: do msg_ring in target task via tw")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If the target ring is configured with IOPOLL, then we always need to hold
the target ring uring_lock before posting CQEs. We could just grab it
unconditionally, but since we don't expect many target rings to be of this
type, make grabbing the uring_lock conditional on the ring type.
Link: https://lore.kernel.org/io-uring/Y8krlYa52%2F0YGqkg@ip-172-31-85-199.ec2.internal/
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In preparation for needing them somewhere else, move them and get rid of
the unused 'issue_flags' for the unlock side.
No functional changes in this patch.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Patch series "mm/nommu: don't use VM_MAYSHARE for MAP_PRIVATE mappings".
Trying to reduce the confusion around VM_SHARED and VM_MAYSHARE first
requires !CONFIG_MMU to stop using VM_MAYSHARE for MAP_PRIVATE mappings.
CONFIG_MMU only sets VM_MAYSHARE for MAP_SHARED mappings.
This paves the way for further VM_MAYSHARE and VM_SHARED cleanups: for
example, renaming VM_MAYSHARED to VM_MAP_SHARED to make it cleaner what is
actually means.
Let's first get the weird case out of the way and not use VM_MAYSHARE in
MAP_PRIVATE mappings, using a new VM_MAYOVERLAY flag instead.
This patch (of 3):
We want to stop using VM_MAYSHARE in private mappings to pave the way for
clarifying the semantics of VM_MAYSHARE vs. VM_SHARED and reduce the
confusion. While CONFIG_MMU uses VM_MAYSHARE to represent MAP_SHARED,
!CONFIG_MMU also sets VM_MAYSHARE for selected R/O private file mappings
that are an effective overlay of a file mapping.
Let's factor out all relevant VM_MAYSHARE checks in !CONFIG_MMU code into
is_nommu_shared_mapping() first.
Note that whenever VM_SHARED is set, VM_MAYSHARE must be set as well
(unless there is a serious BUG). So there is not need to test for
VM_SHARED manually.
No functional change intended.
Link: https://lkml.kernel.org/r/20230102160856.500584-1-david@redhat.com
Link: https://lkml.kernel.org/r/20230102160856.500584-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Nicolas Pitre <nico@fluxnic.net>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
syzbot reports an issue with overflow filling for IOPOLL:
WARNING: CPU: 0 PID: 28 at io_uring/io_uring.c:734 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734
CPU: 0 PID: 28 Comm: kworker/u4:1 Not tainted 6.2.0-rc3-syzkaller-16369-g358a161a6a9e #0
Workqueue: events_unbound io_ring_exit_work
Call trace:
io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734
io_req_cqe_overflow+0x5c/0x70 io_uring/io_uring.c:773
io_fill_cqe_req io_uring/io_uring.h:168 [inline]
io_do_iopoll+0x474/0x62c io_uring/rw.c:1065
io_iopoll_try_reap_events+0x6c/0x108 io_uring/io_uring.c:1513
io_uring_try_cancel_requests+0x13c/0x258 io_uring/io_uring.c:3056
io_ring_exit_work+0xec/0x390 io_uring/io_uring.c:2869
process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
worker_thread+0x340/0x610 kernel/workqueue.c:2436
kthread+0x12c/0x158 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863
There is no real problem for normal IOPOLL as flush is also called with
uring_lock taken, but it's getting more complicated for IOPOLL|SQPOLL,
for which __io_cqring_overflow_flush() happens from the CQ waiting path.
Reported-and-tested-by: syzbot+6805087452d72929404e@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we have multiple requests waiting on the same target poll waitqueue,
then it's quite possible to get a request triggered and get disappointed
in not being able to make any progress with it. If we race in doing so,
we'll potentially leave the poll request on the internal tables, but
removed from the waitqueue. That means that any subsequent trigger of
the poll waitqueue will not kick that request into action, causing an
application to potentially wait for completion of a request that will
never happen.
Fix this by adding a new poll return state, IOU_POLL_REISSUE. Rather
than have complicated logic for how to re-arm a given type of request,
just punt it for a reissue.
While in there, move the 'ret' variable to the only section where it
gets used. This avoids confusion the scope of it.
Cc: stable@vger.kernel.org
Fixes: eb0089d629 ("io_uring: single shot poll removal optimisation")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
A previous commit split the hash table for polled requests into two
parts, but didn't get the fdinfo output updated. This means that it's
less useful for debugging, as we may think a given request is not pending
poll.
Fix this up by dumping the locked hash table contents too.
Fixes: 9ca9fb24d5 ("io_uring: mutex locked poll hashing")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
