==================================================================
BUG: KCSAN: data-race in __io_cqring_fill_event / io_uring_poll

write to 0xffff888126eefc00 of 4 bytes by task 18181 on cpu 0:
 io_get_cqe fs/io_uring.c:1423 [inline]
 __io_cqring_fill_event+0xfb/0x350 fs/io_uring.c:1602
 io_submit_flush_completions+0xb3/0x890 fs/io_uring.c:2136
 __io_queue_sqe+0x241/0x360 fs/io_uring.c:6478
 io_queue_sqe fs/io_uring.c:6507 [inline]
 io_submit_sqe+0x1695/0x3400 fs/io_uring.c:6662
 io_submit_sqes+0x822/0xe50 fs/io_uring.c:6778
 __do_sys_io_uring_enter fs/io_uring.c:9389 [inline]
 __se_sys_io_uring_enter+0x1c7/0xa20 fs/io_uring.c:9332
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:9332
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888126eefc00 of 4 bytes by task 18221 on cpu 1:
 __io_cqring_events fs/io_uring.c:1407 [inline]
 io_cqring_events fs/io_uring.c:2193 [inline]
 io_uring_poll+0xc6/0x150 fs/io_uring.c:8744
 vfs_poll include/linux/poll.h:90 [inline]
 do_pollfd fs/select.c:869 [inline]
 do_poll fs/select.c:917 [inline]
 do_sys_poll+0x622/0xc00 fs/select.c:1011
 __do_sys_ppoll fs/select.c:1117 [inline]
 __se_sys_ppoll+0x169/0x1b0 fs/select.c:1097
 __x64_sys_ppoll+0x63/0x70 fs/select.c:1097
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000006a0 -> 0x000006c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18221 Comm: syz-executor.2 Not tainted 5.14.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================