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BUG: KCSAN: data-race in sock_set_timestamping / udp_sendmsg

write to 0xffff8881003f1be8 of 2 bytes by task 15916 on cpu 0:
 sock_set_timestamping+0x197/0x4c0 net/core/sock.c:883
 sock_setsockopt+0x183f/0x1de0 net/core/sock.c:1135
 __sys_setsockopt+0x14f/0x200 net/socket.c:2172
 __do_sys_setsockopt net/socket.c:2187 [inline]
 __se_sys_setsockopt net/socket.c:2184 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2184
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881003f1be8 of 2 bytes by task 15923 on cpu 1:
 ipcm_init_sk include/net/ip.h:94 [inline]
 udp_sendmsg+0x662/0x1320 net/ipv4/udp.c:1117
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:821
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2409
 ___sys_sendmsg net/socket.c:2463 [inline]
 __sys_sendmmsg+0x388/0x520 net/socket.c:2549
 __do_sys_sendmmsg net/socket.c:2578 [inline]
 __se_sys_sendmmsg net/socket.c:2575 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2575
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000 -> 0x474c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15923 Comm: syz-executor.1 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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