KCSAN: data-race in io_cqring_overflow_flush / io_submit_sqes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3cea11cd Linux 5.10-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12d508a4500000
kernel config: https://syzkaller.appspot.com/x/.config?x=76dfc991796328d4
dashboard link: https://syzkaller.appspot.com/bug?extid=6678a9927846108ce058
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+6678a9...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in io_cqring_overflow_flush / io_submit_sqes

read-write to 0xffff88810a5adc44 of 1 bytes by task 14372 on cpu 1:
io_cqring_overflow_flush+0x95/0x720 fs/io_uring.c:1614
io_uring_cancel_task_requests fs/io_uring.c:8604 [inline]
__io_uring_files_cancel+0x17e/0x1310 fs/io_uring.c:8683
io_uring_files_cancel include/linux/io_uring.h:50 [inline]
exit_files+0x6a/0xc0 fs/file.c:456
do_exit+0x422/0x15a0 kernel/exit.c:801
do_group_exit+0xc8/0x170 kernel/exit.c:903
get_signal+0xf9b/0x1510 kernel/signal.c:2757
arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810a5adc44 of 1 bytes by task 14412 on cpu 0:
io_check_restriction fs/io_uring.c:6412 [inline]
io_init_req fs/io_uring.c:6462 [inline]
io_submit_sqes+0x6a3/0x1300 fs/io_uring.c:6539
__do_sys_io_uring_enter fs/io_uring.c:8870 [inline]
__se_sys_io_uring_enter+0x4c1/0xa60 fs/io_uring.c:8819
__x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:8819
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: 0 PID: 14412 Comm: syz-executor.5 Not tainted 5.10.0-rc2-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.