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BUG: KCSAN: data-race in __io_cqring_fill_event / io_uring_poll

write to 0xffff8881070bba00 of 4 bytes by task 448 on cpu 0:
 io_get_cqe fs/io_uring.c:1656 [inline]
 __io_cqring_fill_event+0xf9/0x380 fs/io_uring.c:1834
 __io_submit_flush_completions fs/io_uring.c:2372 [inline]
 io_submit_flush_completions+0x82/0x2c0 fs/io_uring.c:1202
 tctx_task_work+0xb7/0x410 fs/io_uring.c:2183
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_signal include/linux/tracehook.h:214 [inline]
 handle_signal_work kernel/entry/common.c:146 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x102/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881070bba00 of 4 bytes by task 32677 on cpu 1:
 __io_cqring_events fs/io_uring.c:1640 [inline]
 io_cqring_events fs/io_uring.c:2416 [inline]
 io_uring_poll+0xc6/0x146 fs/io_uring.c:9378
 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+0x4b8/0xad0 fs/select.c:1011
 __do_sys_ppoll fs/select.c:1117 [inline]
 __se_sys_ppoll+0x18b/0x1d0 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+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000030 -> 0x00000033

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 32677 Comm: syz-executor.4 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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