linux/io_uring
Pavel Begunkov 544d163d65 io_uring: lock overflowing for IOPOLL
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>
2023-01-13 07:32:46 -07:00
..
advise.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
advise.h
alloc_cache.h
cancel.c io_uring/cancel: re-grab ctx mutex after finishing wait 2022-12-21 13:31:40 -07:00
cancel.h
epoll.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
epoll.h
fdinfo.c io_uring/fdinfo: include locked hash table in fdinfo output 2023-01-10 10:24:52 -07:00
fdinfo.h
filetable.c io_uring/filetable: fix file reference underflow 2022-11-25 06:54:46 -07:00
filetable.h io_uring: kill hot path fixed file bitmap debug checks 2022-10-16 17:07:53 -06:00
fs.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
fs.h
io_uring.c io_uring: fix CQ waiting timeout handling 2023-01-05 08:04:47 -07:00
io_uring.h io_uring: lockdep annotate CQ locking 2023-01-03 19:05:41 -07:00
io-wq.c io_uring/io-wq: only free worker if it was allocated for creation 2023-01-08 10:39:17 -07:00
io-wq.h
kbuf.c io_uring: don't use complete_post in kbuf 2022-11-25 06:11:15 -07:00
kbuf.h io_uring: allow buffer recycling in READV 2022-09-21 10:30:43 -06:00
Makefile
msg_ring.c io_uring/msg_ring: flag target ring as having task_work, if needed 2022-12-08 09:36:02 -07:00
msg_ring.h io_uring: get rid of double locking 2022-12-07 06:47:13 -07:00
net.c io_uring/net: fix cleanup after recycle 2022-12-19 08:28:28 -07:00
net.h io_uring/net: zerocopy sendmsg 2022-09-21 13:15:02 -06:00
nop.c
nop.h
notif.c io_uring/net: move mm accounting to a slower path 2022-11-21 07:38:31 -07:00
notif.h io_uring: move zc reporting from the hot path 2022-11-21 07:38:31 -07:00
opdef.c io_uring: get rid of double locking 2022-12-07 06:47:13 -07:00
opdef.h io_uring: dont remove file from msg_ring reqs 2022-12-07 06:47:13 -07:00
openclose.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
openclose.h
poll.c io_uring/poll: attempt request issue after racy poll wakeup 2023-01-12 10:35:51 -07:00
poll.h
refs.h
rsrc.c io_uring: use tw for putting rsrc 2022-12-07 06:47:13 -07:00
rsrc.h io_uring: use tw for putting rsrc 2022-12-07 06:47:13 -07:00
rw.c io_uring: lock overflowing for IOPOLL 2023-01-13 07:32:46 -07:00
rw.h io_uring/rw: don't lose partial IO result on fail 2022-09-21 13:15:02 -06:00
slist.h
splice.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
splice.h
sqpoll.c
sqpoll.h
statx.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
statx.h
sync.c io_uring: make io_kiocb_to_cmd() typesafe 2022-08-12 17:01:00 -06:00
sync.h
tctx.c io_uring: remove io_register_submitter 2022-10-07 12:25:30 -06:00
tctx.h io_uring: simplify __io_uring_add_tctx_node 2022-10-07 12:25:30 -06:00
timeout.c io_uring: ease timeout flush locking requirements 2022-12-14 08:53:35 -07:00
timeout.h io_uring: remove unused return from io_disarm_next 2022-09-21 13:15:01 -06:00
uring_cmd.c io_uring: iopoll protect complete_post 2022-11-23 10:45:31 -07:00
uring_cmd.h
xattr.c acl: conver higher-level helpers to rely on mnt_idmap 2022-10-31 17:48:12 +01:00
xattr.h