==================================================================
BUG: KCSAN: data-race in ip_vs_add_service / ip_vs_in_hook

write to 0xffff88811706e804 of 4 bytes by task 3962 on cpu 1:
 ip_vs_add_service+0x9e8/0xa50 net/netfilter/ipvs/ip_vs_ctl.c:1487
 do_ip_vs_set_ctl+0x72b/0x8d0 net/netfilter/ipvs/ip_vs_ctl.c:2807
 nf_setsockopt+0x195/0x1b0 net/netfilter/nf_sockopt.c:101
 ip_setsockopt+0xea/0x100 net/ipv4/ip_sockglue.c:1424
 udp_setsockopt+0x95/0xb0 net/ipv4/udp.c:3053
 sock_common_setsockopt+0x64/0x80 net/core/sock.c:3854
 do_sock_setsockopt net/socket.c:2303 [inline]
 __sys_setsockopt+0x187/0x200 net/socket.c:2328
 __do_sys_setsockopt net/socket.c:2334 [inline]
 __se_sys_setsockopt net/socket.c:2331 [inline]
 __x64_sys_setsockopt+0x66/0x80 net/socket.c:2331
 x64_sys_call+0x282e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:55
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811706e804 of 4 bytes by task 3961 on cpu 0:
 ip_vs_in_hook+0x17f/0x1210 net/netfilter/ipvs/ip_vs_core.c:1943
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0x86/0x1b0 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 __ip_local_out+0x2cc/0x2f0 net/ipv4/ip_output.c:119
 ip_local_out net/ipv4/ip_output.c:128 [inline]
 ip_send_skb+0x30/0x140 net/ipv4/ip_output.c:1502
 udp_send_skb+0x6af/0x9f0 net/ipv4/udp.c:1196
 udp_sendmsg+0x12fa/0x1390 net/ipv4/udp.c:1484
 inet_sendmsg+0xaf/0xd0 net/ipv4/af_inet.c:851
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg+0x102/0x180 net/socket.c:733
 ____sys_sendmsg+0x326/0x4b0 net/socket.c:2573
 ___sys_sendmsg net/socket.c:2627 [inline]
 __sys_sendmmsg+0x227/0x4b0 net/socket.c:2716
 __do_sys_sendmmsg net/socket.c:2743 [inline]
 __se_sys_sendmmsg net/socket.c:2740 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2740
 x64_sys_call+0x29aa/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:308
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3961 Comm: syz.3.155 Not tainted 6.14.0-rc7-syzkaller-00205-g586de92313fc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
net_ratelimit: 15 callbacks suppressed
IPVS: dh: UDP 224.0.0.2:0 - no destination available