io_uring supports using offset == -1 for using the current file position,
and we read that in as part of read/write command setup. For the non-iter
read/write types we pass in NULL for the position pointer, but for the
iter types we should not be passing any anything but 0 for the position
for a stream.
Clear kiocb->ki_pos if the file is a stream, don't leave it as -1. If we
do, then the request will error with -ESPIPE.
Fixes: ba04291eb6 ("io_uring: allow use of offset == -1 to mean file position")
Link: https://github.com/axboe/liburing/discussions/501
Reported-by: Samuel Williams <samuel.williams@oriontransfer.co.nz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
If we successfully cancel a work item but that work item needs to be
processed through task_work, then we can be sleeping uninterruptibly
in io_uring_cancel_generic() and never process it. Hence we don't
make forward progress and we end up with an uninterruptible sleep
warning.
While in there, correct a comment that should be IFF, not IIF.
Reported-and-tested-by: syzbot+21e6887c0be14181206d@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now we have a lot of task_work users, some are just to complete a req
and generate a cqe. Let's put the work to a new tw list which has a
higher priority, so that it can be handled quickly and thus to reduce
avg req latency and users can issue next round of sqes earlier.
An explanatory case:
origin timeline:
submit_sqe-->irq-->add completion task_work
-->run heavy work0~n-->run completion task_work
now timeline:
submit_sqe-->irq-->add completion task_work
-->run completion task_work-->run heavy work0~n
Limitation: this optimization is only for those that submission and
reaping process are in different threads. Otherwise anyhow we have to
submit new sqes after returning to userspace, then the order of TWs
doesn't matter.
Tested this patch(and the following ones) by manually replace
__io_queue_sqe() in io_queue_sqe() by io_req_task_queue() to construct
'heavy' task works. Then test with fio:
ioengine=io_uring
sqpoll=1
thread=1
bs=4k
direct=1
rw=randread
time_based=1
runtime=600
randrepeat=0
group_reporting=1
filename=/dev/nvme0n1
Tried various iodepth.
The peak IOPS for this patch is 710K, while the old one is 665K.
For avg latency, difference shows when iodepth grow:
depth and avg latency(usec):
depth new old
1 7.05 7.10
2 8.47 8.60
4 10.42 10.42
8 13.78 13.22
16 27.41 24.33
32 49.40 53.08
64 102.53 103.36
128 196.98 205.61
256 372.99 414.88
512 747.23 791.30
1024 1472.59 1538.72
2048 3153.49 3329.01
4096 6387.86 6682.54
8192 12150.25 12774.14
16384 23085.58 26044.71
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20211207093951.247840-3-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When iopolling the userspace specifies the minimum number of "events" it
expects. Previously, we had one CQE per request, so the definition of
an "event" was unequivocal, but that's not more the case anymore with
REQ_F_CQE_SKIP.
Currently it counts the number of completed requests, replace it with
the number of posted CQEs. This allows users of the "one CQE per link"
scheme to wait for all N links in a single syscall, which is not
possible without the patch and requires extra context switches.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d5a965c4d2249827392037bbd0186f87fea49c55.1638714983.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We got issue as follows:
================================================================================
UBSAN: Undefined behaviour in ./include/linux/ktime.h:42:14
signed integer overflow:
-4966321760114568020 * 1000000000 cannot be represented in type 'long long int'
CPU: 1 PID: 2186 Comm: syz-executor.2 Not tainted 4.19.90+ #12
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x170/0x1dc lib/dump_stack.c:118
ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
handle_overflow+0x188/0x1dc lib/ubsan.c:192
__ubsan_handle_mul_overflow+0x34/0x44 lib/ubsan.c:213
ktime_set include/linux/ktime.h:42 [inline]
timespec64_to_ktime include/linux/ktime.h:78 [inline]
io_timeout fs/io_uring.c:5153 [inline]
io_issue_sqe+0x42c8/0x4550 fs/io_uring.c:5599
__io_queue_sqe+0x1b0/0xbc0 fs/io_uring.c:5988
io_queue_sqe+0x1ac/0x248 fs/io_uring.c:6067
io_submit_sqe fs/io_uring.c:6137 [inline]
io_submit_sqes+0xed8/0x1c88 fs/io_uring.c:6331
__do_sys_io_uring_enter fs/io_uring.c:8170 [inline]
__se_sys_io_uring_enter fs/io_uring.c:8129 [inline]
__arm64_sys_io_uring_enter+0x490/0x980 fs/io_uring.c:8129
invoke_syscall arch/arm64/kernel/syscall.c:53 [inline]
el0_svc_common+0x374/0x570 arch/arm64/kernel/syscall.c:121
el0_svc_handler+0x190/0x260 arch/arm64/kernel/syscall.c:190
el0_svc+0x10/0x218 arch/arm64/kernel/entry.S:1017
================================================================================
As ktime_set only judge 'secs' if big than KTIME_SEC_MAX, but if we pass
negative value maybe lead to overflow.
To address this issue, we must check if 'sec' is negative.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20211118015907.844807-1-yebin10@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: inconsistent lock state
5.16.0-rc2-syzkaller #0 Not tainted
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
ffff888078e11418 (&ctx->timeout_lock
){?.+.}-{2:2}
, at: io_timeout_fn+0x6f/0x360 fs/io_uring.c:5943
{HARDIRQ-ON-W} state was registered at:
[...]
spin_unlock_irq include/linux/spinlock.h:399 [inline]
__io_poll_remove_one fs/io_uring.c:5669 [inline]
__io_poll_remove_one fs/io_uring.c:5654 [inline]
io_poll_remove_one+0x236/0x870 fs/io_uring.c:5680
io_poll_remove_all+0x1af/0x235 fs/io_uring.c:5709
io_ring_ctx_wait_and_kill+0x1cc/0x322 fs/io_uring.c:9534
io_uring_release+0x42/0x46 fs/io_uring.c:9554
__fput+0x286/0x9f0 fs/file_table.c:280
task_work_run+0xdd/0x1a0 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0xc14/0x2b40 kernel/exit.c:832
674ee8e1b4 ("io_uring: correct link-list traversal locking") fixed a
data race but introduced a possible deadlock and inconsistentcy in irq
states. E.g.
io_poll_remove_all()
spin_lock_irq(timeout_lock)
io_poll_remove_one()
spin_lock/unlock_irq(poll_lock);
spin_unlock_irq(timeout_lock)
Another type of problem is freeing a request while holding
->timeout_lock, which may leads to a deadlock in
io_commit_cqring() -> io_flush_timeouts() and other places.
Having 3 nested locks is also too ugly. Add io_match_task_safe(), which
would briefly take and release timeout_lock for race prevention inside,
so the actuall request cancellation / free / etc. code doesn't have it
taken.
Reported-by: syzbot+ff49a3059d49b0ca0eec@syzkaller.appspotmail.com
Reported-by: syzbot+847f02ec20a6609a328b@syzkaller.appspotmail.com
Reported-by: syzbot+3368aadcd30425ceb53b@syzkaller.appspotmail.com
Reported-by: syzbot+51ce8887cdef77c9ac83@syzkaller.appspotmail.com
Reported-by: syzbot+3cb756a49d2f394a9ee3@syzkaller.appspotmail.com
Fixes: 674ee8e1b4 ("io_uring: correct link-list traversal locking")
Cc: stable@kernel.org # 5.15+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/397f7ebf3f4171f1abe41f708ac1ecb5766f0b68.1637937097.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
WARNING: CPU: 1 PID: 20 at fs/io_uring.c:6269 io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
CPU: 1 PID: 20 Comm: kworker/1:0 Not tainted 5.16.0-rc1-syzkaller #0
Workqueue: events io_fallback_req_func
RIP: 0010:io_try_cancel_userdata+0x3c5/0x640 fs/io_uring.c:6269
Call Trace:
<TASK>
io_req_task_link_timeout+0x6b/0x1e0 fs/io_uring.c:6886
io_fallback_req_func+0xf9/0x1ae fs/io_uring.c:1334
process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298
worker_thread+0x658/0x11f0 kernel/workqueue.c:2445
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
We need original task's context to do cancellations, so if it's dying
and the callback is executed in a fallback mode, fail the cancellation
attempt.
Fixes: 89b263f6d5 ("io_uring: run linked timeouts from task_work")
Cc: stable@kernel.org # 5.15+
Reported-by: syzbot+ab0cfe96c2b3cd1c1153@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4c41c5f379c6941ad5a07cd48cb66ed62199cf7e.1637937097.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Current IOSQE_IO_DRAIN implementation doesn't work well with CQE
skipping and it's not allowed, otherwise some requests might be not
executed until the ring is destroyed and the userspace would hang.
Let's fail all drain requests after seeing IOSQE_CQE_SKIP_SUCCESS at
least once. All drained requests prior to that will get run normally,
so there should be no stalls. However, even though such mixing wouldn't
lead to issues at the moment, it's still not allowed as the behaviour
may change.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bcf7164f8bf3eb54b7bb7b4fd119907fa4d4d43b.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Emitting a CQE is expensive from the kernel perspective. Often, it's
also not convenient for the userspace, spends some cycles on processing
and just complicates the logic. A similar problems goes for linked
requests, where we post an CQE for each request in the link.
Introduce a new flags, IOSQE_CQE_SKIP_SUCCESS, trying to help with it.
When set and a request completed successfully, it won't generate a CQE.
When fails, it produces an CQE, but all following linked requests will
be CQE-less, regardless whether they have IOSQE_CQE_SKIP_SUCCESS or not.
The notion of "fail" is the same as for link failing-cancellation, where
it's opcode dependent, and _usually_ result >= 0 is a success, but not
always.
Linked timeouts are a bit special. When the requests it's linked to was
not attempted to be executed, e.g. failing linked requests, it follows
the description above. Otherwise, whether a linked timeout will post a
completion or not solely depends on IOSQE_CQE_SKIP_SUCCESS of that
linked timeout request. Linked timeout never "fail" during execution, so
for them it's unconditional. It's expected for users to not really care
about the result of it but rely solely on the result of the master
request. Another reason for such a treatment is that it's racy, and the
timeout callback may be running awhile the master request posts its
completion.
use case 1:
If one doesn't care about results of some requests, e.g. normal
timeouts, just set IOSQE_CQE_SKIP_SUCCESS. Error result will still be
posted and need to be handled.
use case 2:
Set IOSQE_CQE_SKIP_SUCCESS for all requests of a link but the last,
and it'll post a completion only for the last one if everything goes
right, otherwise there will be one only one CQE for the first failed
request.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0220fbe06f7cf99e6fc71b4297bb1cb6c0e89c2c.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Split io_cqring_fill_event() into a couple of more targeted functions.
The first on is io_fill_cqe_aux() for completions that are not
associated with request completions and doing the ->cq_extra accounting.
Examples are additional CQEs from multishot poll and rsrc notifications.
The second is io_fill_cqe_req(), should be called when it's a normal
request completion. Nothing more to it at the moment, will be used in
later patches.
The last one is inlined __io_fill_cqe() for a finer grained control,
should be used with caution and in hottest places.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/59a9117a4a44fc9efcf04b3afa51e0d080f5943c.1636559119.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The kernel test robot correctly identifies that we store sqe twice,
remove the earlier one that is done before validating the index.
Fixes: f75d118349 ("io_uring: harder fdinfo sq/cq ring iterating")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
After the assignment, only exit path with label 'err' uses ret as
return value. However,before exiting through this path with label 'err',
ret is assigned with the return value of io_wq_max_workers(). Hence, the
initial assignment is redundant and can be removed.
Signed-off-by: Nghia Le <nghialm78@gmail.com>
Link: https://lore.kernel.org/r/20211102190521.28291-1-nghialm78@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull selinux updates from Paul Moore:
- Add LSM/SELinux/Smack controls and auditing for io-uring.
As usual, the individual commit descriptions have more detail, but we
were basically missing two things which we're adding here:
+ establishment of a proper audit context so that auditing of
io-uring ops works similarly to how it does for syscalls (with
some io-uring additions because io-uring ops are *not* syscalls)
+ additional LSM hooks to enable access control points for some of
the more unusual io-uring features, e.g. credential overrides.
The additional audit callouts and LSM hooks were done in conjunction
with the io-uring folks, based on conversations and RFC patches
earlier in the year.
- Fixup the binder credential handling so that the proper credentials
are used in the LSM hooks; the commit description and the code
comment which is removed in these patches are helpful to understand
the background and why this is the proper fix.
- Enable SELinux genfscon policy support for securityfs, allowing
improved SELinux filesystem labeling for other subsystems which make
use of securityfs, e.g. IMA.
* tag 'selinux-pr-20211101' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
security: Return xattr name from security_dentry_init_security()
selinux: fix a sock regression in selinux_ip_postroute_compat()
binder: use cred instead of task for getsecid
binder: use cred instead of task for selinux checks
binder: use euid from cred instead of using task
LSM: Avoid warnings about potentially unused hook variables
selinux: fix all of the W=1 build warnings
selinux: make better use of the nf_hook_state passed to the NF hooks
selinux: fix race condition when computing ocontext SIDs
selinux: remove unneeded ipv6 hook wrappers
selinux: remove the SELinux lockdown implementation
selinux: enable genfscon labeling for securityfs
Smack: Brutalist io_uring support
selinux: add support for the io_uring access controls
lsm,io_uring: add LSM hooks to io_uring
io_uring: convert io_uring to the secure anon inode interface
fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure()
audit: add filtering for io_uring records
audit,io_uring,io-wq: add some basic audit support to io_uring
audit: prepare audit_context for use in calling contexts beyond syscalls
Pull kiocb->ki_complete() cleanup from Jens Axboe:
"This removes the res2 argument from kiocb->ki_complete().
Only the USB gadget code used it, everybody else passes 0. The USB
guys checked the user gadget code they could find, and everybody just
uses res as expected for the async interface"
* tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-block:
fs: get rid of the res2 iocb->ki_complete argument
usb: remove res2 argument from gadget code completions
Pull io_uring updates from Jens Axboe:
"Light on new features - basically just the hybrid mode support.
Outside of that it's just fixes, cleanups, and performance
improvements.
In detail:
- Add ring related information to the fdinfo output (Hao)
- Hybrid async mode (Hao)
- Support for batched issue on block (me)
- sqe error trace improvement (me)
- IOPOLL efficiency improvements (Pavel)
- submit state cleanups and improvements (Pavel)
- Completion side improvements (Pavel)
- Drain improvements (Pavel)
- Buffer selection cleanups (Pavel)
- Fixed file node improvements (Pavel)
- io-wq setup cancelation fix (Pavel)
- Various other performance improvements and cleanups (Pavel)
- Misc fixes (Arnd, Bixuan, Changcheng, Hao, me, Noah)"
* tag 'for-5.16/io_uring-2021-10-29' of git://git.kernel.dk/linux-block: (97 commits)
io-wq: remove worker to owner tw dependency
io_uring: harder fdinfo sq/cq ring iterating
io_uring: don't assign write hint in the read path
io_uring: clusterise ki_flags access in rw_prep
io_uring: kill unused param from io_file_supports_nowait
io_uring: clean up timeout async_data allocation
io_uring: don't try io-wq polling if not supported
io_uring: check if opcode needs poll first on arming
io_uring: clean iowq submit work cancellation
io_uring: clean io_wq_submit_work()'s main loop
io-wq: use helper for worker refcounting
io_uring: implement async hybrid mode for pollable requests
io_uring: Use ERR_CAST() instead of ERR_PTR(PTR_ERR())
io_uring: split logic of force_nonblock
io_uring: warning about unused-but-set parameter
io_uring: inform block layer of how many requests we are submitting
io_uring: simplify io_file_supports_nowait()
io_uring: combine REQ_F_NOWAIT_{READ,WRITE} flags
io_uring: arm poll for non-nowait files
fs/io_uring: Prioritise checking faster conditions first in io_write
...
Pull block updates from Jens Axboe:
- mq-deadline accounting improvements (Bart)
- blk-wbt timer fix (Andrea)
- Untangle the block layer includes (Christoph)
- Rework the poll support to be bio based, which will enable adding
support for polling for bio based drivers (Christoph)
- Block layer core support for multi-actuator drives (Damien)
- blk-crypto improvements (Eric)
- Batched tag allocation support (me)
- Request completion batching support (me)
- Plugging improvements (me)
- Shared tag set improvements (John)
- Concurrent queue quiesce support (Ming)
- Cache bdev in ->private_data for block devices (Pavel)
- bdev dio improvements (Pavel)
- Block device invalidation and block size improvements (Xie)
- Various cleanups, fixes, and improvements (Christoph, Jackie,
Masahira, Tejun, Yu, Pavel, Zheng, me)
* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
blk-mq-debugfs: Show active requests per queue for shared tags
block: improve readability of blk_mq_end_request_batch()
virtio-blk: Use blk_validate_block_size() to validate block size
loop: Use blk_validate_block_size() to validate block size
nbd: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
block: re-flow blk_mq_rq_ctx_init()
block: prefetch request to be initialized
block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
block: add rq_flags to struct blk_mq_alloc_data
block: add async version of bio_set_polled
block: kill DIO_MULTI_BIO
block: kill unused polling bits in __blkdev_direct_IO()
block: avoid extra iter advance with async iocb
block: Add independent access ranges support
blk-mq: don't issue request directly in case that current is to be blocked
sbitmap: silence data race warning
blk-cgroup: synchronize blkg creation against policy deactivation
block: refactor bio_iov_bvec_set()
block: add single bio async direct IO helper
...
Pull memory folios from Matthew Wilcox:
"Add memory folios, a new type to represent either order-0 pages or the
head page of a compound page. This should be enough infrastructure to
support filesystems converting from pages to folios.
The point of all this churn is to allow filesystems and the page cache
to manage memory in larger chunks than PAGE_SIZE. The original plan
was to use compound pages like THP does, but I ran into problems with
some functions expecting only a head page while others expect the
precise page containing a particular byte.
The folio type allows a function to declare that it's expecting only a
head page. Almost incidentally, this allows us to remove various calls
to VM_BUG_ON(PageTail(page)) and compound_head().
This converts just parts of the core MM and the page cache. For 5.17,
we intend to convert various filesystems (XFS and AFS are ready; other
filesystems may make it) and also convert more of the MM and page
cache to folios. For 5.18, multi-page folios should be ready.
The multi-page folios offer some improvement to some workloads. The
80% win is real, but appears to be an artificial benchmark (postgres
startup, which isn't a serious workload). Real workloads (eg building
the kernel, running postgres in a steady state, etc) seem to benefit
between 0-10%. I haven't heard of any performance losses as a result
of this series. Nobody has done any serious performance tuning; I
imagine that tweaking the readahead algorithm could provide some more
interesting wins. There are also other places where we could choose to
create large folios and currently do not, such as writes that are
larger than PAGE_SIZE.
I'd like to thank all my reviewers who've offered review/ack tags:
Christoph Hellwig, David Howells, Jan Kara, Jeff Layton, Johannes
Weiner, Kirill A. Shutemov, Michal Hocko, Mike Rapoport, Vlastimil
Babka, William Kucharski, Yu Zhao and Zi Yan.
I'd also like to thank those who gave feedback I incorporated but
haven't offered up review tags for this part of the series: Nick
Piggin, Mel Gorman, Ming Lei, Darrick Wong, Ted Ts'o, John Hubbard,
Hugh Dickins, and probably a few others who I forget"
* tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache: (90 commits)
mm/writeback: Add folio_write_one
mm/filemap: Add FGP_STABLE
mm/filemap: Add filemap_get_folio
mm/filemap: Convert mapping_get_entry to return a folio
mm/filemap: Add filemap_add_folio()
mm/filemap: Add filemap_alloc_folio
mm/page_alloc: Add folio allocation functions
mm/lru: Add folio_add_lru()
mm/lru: Convert __pagevec_lru_add_fn to take a folio
mm: Add folio_evictable()
mm/workingset: Convert workingset_refault() to take a folio
mm/filemap: Add readahead_folio()
mm/filemap: Add folio_mkwrite_check_truncate()
mm/filemap: Add i_blocks_per_folio()
mm/writeback: Add folio_redirty_for_writepage()
mm/writeback: Add folio_account_redirty()
mm/writeback: Add folio_clear_dirty_for_io()
mm/writeback: Add folio_cancel_dirty()
mm/writeback: Add folio_account_cleaned()
mm/writeback: Add filemap_dirty_folio()
...
The ring iteration is racy, which isn't necessarily a problem except it
can cause us to iterate the whole thing. That isn't desired or ideal,
and it can lead to excessive runtimes of reading fdinfo.
Cap the iteration at tail - head OR the ring size. While in there, clean
up the ring masking and just dump the raw values along with the masks.
That provides more useful debug info.
Fixes: 83f84356bc ("io_uring: add more uring info to fdinfo for debug")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.
Now that everybody is passing in zero, kill off the extra argument.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
