syzbot

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BUG: KCSAN: data-race in packet_sendmsg / sock_setsockopt

read to 0xffff888125091a68 of 2 bytes by task 22911 on cpu 1:
 sockcm_init include/net/sock.h:1645 [inline]
 packet_snd net/packet/af_packet.c:2867 [inline]
 packet_sendmsg+0x138d/0x3af0 net/packet/af_packet.c:2984
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x59d/0x5d0 net/socket.c:2311
 __sys_sendmsg+0xa0/0x160 net/socket.c:2356
 __do_sys_sendmsg net/socket.c:2365 [inline]
 __se_sys_sendmsg net/socket.c:2363 [inline]
 __x64_sys_sendmsg+0x51/0x70 net/socket.c:2363
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff888125091a68 of 2 bytes by task 22909 on cpu 0:
 sock_setsockopt+0x4b1/0x1850 net/core/sock.c:960
 __sys_setsockopt+0x34b/0x370 net/socket.c:2080
 __do_sys_setsockopt net/socket.c:2100 [inline]
 __se_sys_setsockopt net/socket.c:2097 [inline]
 __x64_sys_setsockopt+0x70/0x90 net/socket.c:2097
 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: 22909 Comm: syz-executor.2 Not tainted 5.4.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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