KCSAN: data-race in io_worker_handle_work / io_wqe_wake_worker (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: e87297fa Merge tag 'drm-fixes-2020-12-04' of git://anongit..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=125ddc6d500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c949fed53798f819
dashboard link: https://syzkaller.appspot.com/bug?extid=9aa3af050e63ee9d5e7d
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project.git 913f6005669cfb590c99865a90bc51ed0983d09d)
CC: [ax...@kernel.dk io-u...@vger.kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9aa3af...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in io_worker_handle_work / io_wqe_wake_worker

read-write to 0xffff88810e773444 of 4 bytes by task 8533 on cpu 0:
__io_worker_busy fs/io-wq.c:367 [inline]
io_worker_handle_work+0x4fd/0x1000 fs/io-wq.c:548
io_wqe_worker+0x202/0x810 fs/io-wq.c:614
kthread+0x1fd/0x220 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88810e773444 of 4 bytes by task 8506 on cpu 1:
io_wqe_wake_worker+0x163/0x220 fs/io-wq.c:308
io_wqe_enqueue+0x2a5/0x320 fs/io-wq.c:919
io_wq_enqueue+0x3a/0x40 fs/io-wq.c:926
__io_queue_async_work fs/io_uring.c:1432 [inline]
io_queue_async_work+0x189/0x660 fs/io_uring.c:1442
__io_queue_sqe+0xac4/0x1160 fs/io_uring.c:6244
io_queue_sqe+0x1e2/0x580 fs/io_uring.c:6298
io_submit_sqe+0x385/0x8f0 fs/io_uring.c:6367
io_submit_sqes+0x9a8/0x1720 fs/io_uring.c:6596
__do_sys_io_uring_enter fs/io_uring.c:8983 [inline]
__se_sys_io_uring_enter+0x52c/0xac0 fs/io_uring.c:8932
__x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:8932
do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8506 Comm: syz-executor.0 Not tainted 5.10.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.