linux-stable.git/io_uring, branch v6.2.8 Linux kernel stable tree io_uring/msg_ring: let target know allocated index 2023-03-22T12:38:08+00:00 Pavel Begunkov asml.silence@gmail.com 2023-03-16T12:11:42+00:00 b0fb2373c3d874a0a3e69e067fc120a1ab23700b commit 5da28edd7bd5518f97175ecea77615bb729a7a28 upstream. 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: e6130eba8a848 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5da28edd7bd5518f97175ecea77615bb729a7a28 upstream.

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: e6130eba8a848 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring/uring_cmd: ensure that device supports IOPOLL 2023-03-17T07:57:45+00:00 Jens Axboe axboe@kernel.dk 2023-03-08T16:26:13+00:00 67c1a7decfced0e3e8aaad55ab0cb4fb786a15fa commit 03b3d6be73e81ddb7c2930d942cdd17f4cfd5ba5 upstream. 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: 5756a3a7e713 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 03b3d6be73e81ddb7c2930d942cdd17f4cfd5ba5 upstream.

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: 5756a3a7e713 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring: fix size calculation when registering buf ring 2023-03-11T12:50:35+00:00 Wojciech Lukowicz wlukowicz01@gmail.com 2023-02-18T18:41:41+00:00 94f7ac92d1f054ce1a998677012f138c875ddcb0 [ Upstream commit 48ba08374e779421ca34bd14b4834aae19fc3e6a ] 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: c7fb19428d67 ("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> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 48ba08374e779421ca34bd14b4834aae19fc3e6a ]

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: c7fb19428d67 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
io_uring: mark task TASK_RUNNING before handling resume/task work 2023-03-10T08:29:28+00:00 Jens Axboe axboe@kernel.dk 2023-02-06T15:20:46+00:00 eaa2a19d24f1eb3d2b7bb83ed2c150e23505bd1a commit 2f2bb1ffc9983e227424d0787289da5483b0c74f upstream. 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: b5d3ae202fbf ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 2f2bb1ffc9983e227424d0787289da5483b0c74f upstream.

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: b5d3ae202fbf ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring: fix fget leak when fs don't support nowait buffered read 2023-03-10T08:29:24+00:00 Joseph Qi joseph.qi@linux.alibaba.com 2023-02-28T04:54:59+00:00 10fb2e16ee6ffaf1716b9e90d007e6b300bfa457 commit 54aa7f2330b82884f4a1afce0220add6e8312f8b upstream. 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 a196c78b5443 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: a196c78b5443 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 54aa7f2330b82884f4a1afce0220add6e8312f8b upstream.

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 a196c78b5443 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: a196c78b5443 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring/poll: allow some retries for poll triggering spuriously 2023-03-10T08:29:24+00:00 Jens Axboe axboe@kernel.dk 2023-02-25T19:53:53+00:00 6f1e7441712234b0bed52904e2c7d4cca3e4d2b4 commit c16bda37594f83147b167d381d54c010024efecf upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c16bda37594f83147b167d381d54c010024efecf upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring: remove MSG_NOSIGNAL from recvmsg 2023-03-10T08:29:24+00:00 David Lamparter equinox@diac24.net 2023-02-24T15:01:24+00:00 9b5ed6b4e6c3ad9b2ca8d5f6594a6ab4a2cd9531 commit 7605c43d67face310b4b87dee1a28bc0c8cd8c0f upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7605c43d67face310b4b87dee1a28bc0c8cd8c0f upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring/rsrc: disallow multi-source reg buffers 2023-03-10T08:29:24+00:00 Pavel Begunkov asml.silence@gmail.com 2023-02-22T14:36:48+00:00 e559fb5d87eb5dce2d414aca400f343e1cac2761 commit edd478269640b360c6f301f2baa04abdda563ef3 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit edd478269640b360c6f301f2baa04abdda563ef3 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring: add reschedule point to handle_tw_list() 2023-03-10T08:29:24+00:00 Jens Axboe axboe@kernel.dk 2023-01-27T16:50:31+00:00 bb94f3c10a26a9213633da6aa03d4b4a484ae495 commit f58680085478dd292435727210122960d38e8014 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f58680085478dd292435727210122960d38e8014 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
io_uring: add a conditional reschedule to the IOPOLL cancelation loop 2023-03-10T08:29:24+00:00 Jens Axboe axboe@kernel.dk 2023-01-27T16:28:13+00:00 300c2f021ee837689ffb1f5d0ac760967276e315 commit fcc926bb857949dbfa51a7d95f3f5ebc657f198c upstream. If the kernel is configured with CONFIG_PREEMPT_NONE, we could be sitting in a tight loop reaping events but not giving them a chance to finish. This results in a trace ala: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 2-...!: (5249 ticks this GP) idle=935c/1/0x4000000000000000 softirq=4265/4274 fqs=1 (t=5251 jiffies g=465 q=4135 ncpus=4) rcu: rcu_sched kthread starved for 5249 jiffies! g465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_sched state:R running task stack:0 pid:12 ppid:2 flags:0x00000008 Call trace: __switch_to+0xb0/0xc8 __schedule+0x43c/0x520 schedule+0x4c/0x98 schedule_timeout+0xbc/0xdc rcu_gp_fqs_loop+0x308/0x344 rcu_gp_kthread+0xd8/0xf0 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 0: task:kworker/u8:10 state:R running task stack:0 pid:89 ppid:2 flags:0x0000000a Workqueue: events_unbound io_ring_exit_work Call trace: __switch_to+0xb0/0xc8 0xffff0000c8fefd28 CPU: 2 PID: 95 Comm: kworker/u8:13 Not tainted 6.2.0-rc5-00042-g40316e337c80-dirty #2759 Hardware name: linux,dummy-virt (DT) Workqueue: events_unbound io_ring_exit_work pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : io_do_iopoll+0x344/0x360 lr : io_do_iopoll+0xb8/0x360 sp : ffff800009bebc60 x29: ffff800009bebc60 x28: 0000000000000000 x27: 0000000000000000 x26: ffff0000c0f67d48 x25: ffff0000c0f67840 x24: ffff800008950024 x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c27d3200 x20: ffff0000c0f67840 x19: ffff0000c0f67800 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000001 x13: 0000000000000001 x12: 0000000000000000 x11: 0000000000000179 x10: 0000000000000870 x9 : ffff800009bebd60 x8 : ffff0000c27d3ad0 x7 : fefefefefefefeff x6 : 0000646e756f626e x5 : ffff0000c0f67840 x4 : 0000000000000000 x3 : ffff0000c2398000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: io_do_iopoll+0x344/0x360 io_uring_try_cancel_requests+0x21c/0x334 io_ring_exit_work+0x90/0x40c process_one_work+0x1a4/0x254 worker_thread+0x1ec/0x258 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 Add a cond_resched() in the cancelation IOPOLL loop to fix this. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit fcc926bb857949dbfa51a7d95f3f5ebc657f198c upstream.

If the kernel is configured with CONFIG_PREEMPT_NONE, we could be
sitting in a tight loop reaping events but not giving them a chance to
finish. This results in a trace ala:

rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 	2-...!: (5249 ticks this GP) idle=935c/1/0x4000000000000000 softirq=4265/4274 fqs=1
	(t=5251 jiffies g=465 q=4135 ncpus=4)
rcu: rcu_sched kthread starved for 5249 jiffies! g465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_sched       state:R  running task     stack:0     pid:12    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0xb0/0xc8
 __schedule+0x43c/0x520
 schedule+0x4c/0x98
 schedule_timeout+0xbc/0xdc
 rcu_gp_fqs_loop+0x308/0x344
 rcu_gp_kthread+0xd8/0xf0
 kthread+0xb8/0xc8
 ret_from_fork+0x10/0x20
rcu: Stack dump where RCU GP kthread last ran:
Task dump for CPU 0:
task:kworker/u8:10   state:R  running task     stack:0     pid:89    ppid:2      flags:0x0000000a
Workqueue: events_unbound io_ring_exit_work
Call trace:
 __switch_to+0xb0/0xc8
 0xffff0000c8fefd28
CPU: 2 PID: 95 Comm: kworker/u8:13 Not tainted 6.2.0-rc5-00042-g40316e337c80-dirty #2759
Hardware name: linux,dummy-virt (DT)
Workqueue: events_unbound io_ring_exit_work
pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
pc : io_do_iopoll+0x344/0x360
lr : io_do_iopoll+0xb8/0x360
sp : ffff800009bebc60
x29: ffff800009bebc60 x28: 0000000000000000 x27: 0000000000000000
x26: ffff0000c0f67d48 x25: ffff0000c0f67840 x24: ffff800008950024
x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c27d3200
x20: ffff0000c0f67840 x19: ffff0000c0f67800 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 0000000000000001 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000179 x10: 0000000000000870 x9 : ffff800009bebd60
x8 : ffff0000c27d3ad0 x7 : fefefefefefefeff x6 : 0000646e756f626e
x5 : ffff0000c0f67840 x4 : 0000000000000000 x3 : ffff0000c2398000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
 io_do_iopoll+0x344/0x360
 io_uring_try_cancel_requests+0x21c/0x334
 io_ring_exit_work+0x90/0x40c
 process_one_work+0x1a4/0x254
 worker_thread+0x1ec/0x258
 kthread+0xb8/0xc8
 ret_from_fork+0x10/0x20

Add a cond_resched() in the cancelation IOPOLL loop to fix this.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>