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BUG: KCSAN: data-race in do_epoll_wait / ep_poll_callback

write to 0xffff88812461ddd0 of 8 bytes by task 8642 on cpu 0:
 list_add_tail_lockless fs/eventpoll.c:1158 [inline]
 ep_poll_callback+0x29c/0x510 fs/eventpoll.c:1248
 __wake_up_common+0xbc/0x130 kernel/sched/wait.c:93
 __wake_up_common_lock kernel/sched/wait.c:123 [inline]
 __wake_up_sync_key+0x83/0xc0 kernel/sched/wait.c:190
 sock_def_readable+0x61/0xe0 net/core/sock.c:2909
 tcp_data_ready net/ipv4/tcp_input.c:4796 [inline]
 tcp_rcv_established+0x13c0/0x1520 net/ipv4/tcp_input.c:5725
 tcp_v4_do_rcv+0x25e/0x480 net/ipv4/tcp_ipv4.c:1641
 sk_backlog_rcv include/net/sock.h:997 [inline]
 __release_sock+0xf5/0x260 net/core/sock.c:2550
 release_sock+0x40/0x110 net/core/sock.c:3066
 tcp_recvmsg+0x16ba/0x1c10 net/ipv4/tcp.c:2252
 inet_recvmsg+0xa9/0x210 net/ipv4/af_inet.c:845
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_read_iter+0x19c/0x1e0 net/socket.c:977
 call_read_iter include/linux/fs.h:1902 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x523/0x590 fs/read_write.c:481
 ksys_read+0xce/0x180 fs/read_write.c:607
 __do_sys_read fs/read_write.c:617 [inline]
 __se_sys_read fs/read_write.c:615 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:615
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88812461ddd0 of 8 bytes by task 8652 on cpu 1:
 list_empty_careful include/linux/list.h:300 [inline]
 ep_events_available fs/eventpoll.c:379 [inline]
 ep_poll fs/eventpoll.c:1855 [inline]
 do_epoll_wait+0x2e2/0x870 fs/eventpoll.c:2333
 __do_sys_epoll_pwait fs/eventpoll.c:2364 [inline]
 __se_sys_epoll_pwait fs/eventpoll.c:2350 [inline]
 __x64_sys_epoll_pwait+0x92/0x150 fs/eventpoll.c:2350
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8652 Comm: syz-fuzzer Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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