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BUG: KCSAN: data-race in do_epoll_wait / ep_poll_callback

write to 0xffff888138e4ba68 of 4 bytes by task 27942 on cpu 1:
 ep_send_events fs/eventpoll.c:1745 [inline]
 ep_poll fs/eventpoll.c:1864 [inline]
 do_epoll_wait+0x805/0xe70 fs/eventpoll.c:2318
 do_epoll_pwait fs/eventpoll.c:2352 [inline]
 __do_sys_epoll_pwait fs/eventpoll.c:2365 [inline]
 __se_sys_epoll_pwait+0x15f/0x280 fs/eventpoll.c:2359
 __x64_sys_epoll_pwait+0x78/0x90 fs/eventpoll.c:2359
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888138e4ba68 of 4 bytes by task 27916 on cpu 0:
 ep_poll_callback+0x4b5/0x5a0 fs/eventpoll.c:1246
 __wake_up_common kernel/sched/wait.c:89 [inline]
 __wake_up_common_lock kernel/sched/wait.c:106 [inline]
 __wake_up_sync_key+0x50/0x80 kernel/sched/wait.c:173
 unix_write_space+0xcd/0x140 net/unix/af_unix.c:551
 sock_wfree+0x119/0x330 net/core/sock.c:2477
 unix_destruct_scm+0x12e/0x160 net/unix/scm.c:153
 skb_release_head_state+0xb7/0x1a0 net/core/skbuff.c:1044
 skb_release_all net/core/skbuff.c:1056 [inline]
 __kfree_skb+0x16/0x140 net/core/skbuff.c:1072
 kfree_skb_reason+0xae/0x2b0 net/core/skbuff.c:1108
 kfree_skb include/linux/skbuff.h:1234 [inline]
 unix_release_sock+0x63d/0x780 net/unix/af_unix.c:663
 unix_release+0x52/0x70 net/unix/af_unix.c:1066
 __sock_release net/socket.c:659 [inline]
 sock_close+0x64/0x140 net/socket.c:1419
 __fput+0x299/0x630 fs/file_table.c:394
 __fput_sync+0x44/0x50 fs/file_table.c:475
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close+0xfa/0x1a0 fs/open.c:1575
 __x64_sys_close+0x1f/0x30 fs/open.c:1575
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xe000001f -> 0xe0000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27916 Comm: syz-executor.2 Not tainted 6.6.0-syzkaller-14651-gd2f51b3516da #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
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