syzbot

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BUG: KCSAN: data-race in datagram_poll / inet_shutdown

write to 0xffff888120f78b6a of 1 bytes by task 29004 on cpu 1:
 inet_shutdown+0x105/0x270 net/ipv4/af_inet.c:877
 __sys_shutdown+0xa2/0x130 net/socket.c:2160
 __do_sys_shutdown net/socket.c:2168 [inline]
 __se_sys_shutdown net/socket.c:2166 [inline]
 __x64_sys_shutdown+0x3a/0x50 net/socket.c:2166
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888120f78b6a of 1 bytes by task 29002 on cpu 0:
 datagram_poll+0xf6/0x330 net/core/datagram.c:774
 udp_poll+0x43/0x150 net/ipv4/udp.c:2723
 sock_poll+0xed/0x250 net/socket.c:1256
 vfs_poll include/linux/poll.h:90 [inline]
 do_pollfd fs/select.c:859 [inline]
 do_poll fs/select.c:907 [inline]
 do_sys_poll+0x4ac/0x990 fs/select.c:1001
 __do_sys_poll fs/select.c:1059 [inline]
 __se_sys_poll fs/select.c:1047 [inline]
 __x64_sys_poll+0x10f/0x250 fs/select.c:1047
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29002 Comm: syz-executor.2 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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