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BUG: KCSAN: data-race in __io_fill_cqe_req / io_uring_poll

write to 0xffff8881420a0a00 of 4 bytes by task 21861 on cpu 0:
 io_get_cqe fs/io_uring.c:1820 [inline]
 __io_fill_cqe fs/io_uring.c:2030 [inline]
 __io_fill_cqe_req+0x129/0x3a0 fs/io_uring.c:2043
 __io_req_complete_post+0x65/0x580 fs/io_uring.c:2066
 io_req_complete_post fs/io_uring.c:2100 [inline]
 io_req_complete_failed+0xa1/0x260 fs/io_uring.c:2131
 __io_queue_sqe fs/io_uring.c:7529 [inline]
 io_queue_sqe fs/io_uring.c:7554 [inline]
 io_submit_sqe+0x3d25/0x4300 fs/io_uring.c:7759
 io_submit_sqes+0x25e/0x7e0 fs/io_uring.c:7865
 __do_sys_io_uring_enter fs/io_uring.c:10810 [inline]
 __se_sys_io_uring_enter+0x2cb/0xc70 fs/io_uring.c:10736
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:10736
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881420a0a00 of 4 bytes by task 21849 on cpu 1:
 __io_cqring_events fs/io_uring.c:1804 [inline]
 io_cqring_events fs/io_uring.c:2725 [inline]
 io_uring_poll+0xc5/0x150 fs/io_uring.c:10010
 vfs_poll include/linux/poll.h:88 [inline]
 do_pollfd fs/select.c:873 [inline]
 do_poll fs/select.c:921 [inline]
 do_sys_poll+0x6d5/0xca0 fs/select.c:1015
 __do_sys_ppoll fs/select.c:1121 [inline]
 __se_sys_ppoll+0x195/0x1d0 fs/select.c:1101
 __x64_sys_ppoll+0x63/0x70 fs/select.c:1101
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000089e -> 0x000008c1

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21849 Comm: syz-executor.0 Not tainted 5.18.0-rc7-syzkaller-00006-g210e04ff7681-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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