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

write to 0xffff888131c30c80 of 4 bytes by task 9114 on cpu 0:
 io_get_cqring fs/io_uring.c:1368 [inline]
 __io_cqring_fill_event+0xfd/0x350 fs/io_uring.c:1550
 io_req_complete_post+0x58/0x540 fs/io_uring.c:1574
 __io_req_complete fs/io_uring.c:1629 [inline]
 __io_complete_rw+0x3ba/0x480 fs/io_uring.c:2479
 io_complete_rw+0x1b/0x20 fs/io_uring.c:2486
 io_rw_done fs/io_uring.c:2720 [inline]
 kiocb_done+0x1b1/0x420 fs/io_uring.c:2744
 io_read fs/io_uring.c:3325 [inline]
 io_issue_sqe+0x399d/0x6620 fs/io_uring.c:6106
 __io_queue_sqe+0xe9/0x360 fs/io_uring.c:6404
 io_queue_sqe fs/io_uring.c:6453 [inline]
 io_submit_sqe+0x18b7/0x33d0 fs/io_uring.c:6620
 io_submit_sqes+0x5bd/0xbd0 fs/io_uring.c:6728
 __do_sys_io_uring_enter fs/io_uring.c:9294 [inline]
 __se_sys_io_uring_enter+0x1e1/0xa80 fs/io_uring.c:9236
 __x64_sys_io_uring_enter+0x74/0x80 fs/io_uring.c:9236
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888131c30c80 of 4 bytes by task 9149 on cpu 1:
 __io_cqring_events fs/io_uring.c:1352 [inline]
 io_cqring_events fs/io_uring.c:2190 [inline]
 io_uring_poll+0xcf/0x160 fs/io_uring.c:8637
 vfs_poll include/linux/poll.h:90 [inline]
 io_poll_rewait fs/io_uring.c:4839 [inline]
 io_poll_task_func+0xf4/0x7c0 fs/io_uring.c:4918
 __tctx_task_work fs/io_uring.c:1899 [inline]
 tctx_task_work+0x1d4/0x3d0 fs/io_uring.c:1913
 task_work_run+0xae/0x130 kernel/task_work.c:161
 io_run_task_work fs/io_uring.c:2230 [inline]
 io_sq_thread+0x99f/0x10b0 fs/io_uring.c:6866
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9149 Comm: iou-sqp-9126 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================