syzbot

BUG: KCSAN: data-race in __ip4_datagram_connect / __ip_make_skb

write to 0xffff88810110ec6a of 2 bytes by task 16734 on cpu 0:
 __ip4_datagram_connect+0x753/0x7b0 net/ipv4/datagram.c:74
 ip4_datagram_connect+0x2a/0x40 net/ipv4/datagram.c:88
 inet_dgram_connect+0x107/0x190 net/ipv4/af_inet.c:576
 __sys_connect_file net/socket.c:1979 [inline]
 __sys_connect+0x197/0x1b0 net/socket.c:1996
 __do_sys_connect net/socket.c:2006 [inline]
 __se_sys_connect net/socket.c:2003 [inline]
 __x64_sys_connect+0x3d/0x50 net/socket.c:2003
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read-write to 0xffff88810110ec6a of 2 bytes by task 16735 on cpu 1:
 ip_select_ident_segs include/net/ip.h:533 [inline]
 ip_select_ident include/net/ip.h:547 [inline]
 __ip_make_skb+0x867/0xb50 net/ipv4/ip_output.c:1541
 ip_make_skb+0x238/0x2c0 net/ipv4/ip_output.c:1645
 udp_sendmsg+0x1121/0x1200 net/ipv4/udp.c:1249
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2492
 ___sys_sendmsg net/socket.c:2546 [inline]
 __sys_sendmmsg+0x27c/0x4a0 net/socket.c:2632
 __do_sys_sendmmsg net/socket.c:2661 [inline]
 __se_sys_sendmmsg net/socket.c:2658 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2658
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0xe0f3 -> 0x4f3e

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16735 Comm: syz-executor.3 Not tainted 5.18.0-syzkaller-11080-g664a393a2663-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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