syzbot

==================================================================
BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

read-write to 0xffff8881267c9158 of 8 bytes by task 14833 on cpu 1:
 ip_tunnel_xmit+0x10ad/0x16f0 net/ipv4/ip_tunnel.c:822
 sit_tunnel_xmit+0x5a0/0x1410
 __netdev_start_xmit include/linux/netdevice.h:4840 [inline]
 netdev_start_xmit include/linux/netdevice.h:4854 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3590
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
 __dev_queue_xmit+0x84c/0xfe0 net/core/dev.c:4256
 dev_queue_xmit include/linux/netdevice.h:3008 [inline]
 neigh_connected_output+0x266/0x2a0 net/core/neighbour.c:1581
 neigh_output include/net/neighbour.h:546 [inline]
 ip_finish_output2+0x74d/0x850 net/ipv4/ip_output.c:228
 ip_finish_output+0xf3/0x250 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0xf3/0x1a0 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:445 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb net/ipv4/ip_output.c:1586 [inline]
 ip_push_pending_frames+0xa3/0x120 net/ipv4/ip_output.c:1606
 raw_sendmsg+0xc4f/0xd50 net/ipv4/raw.c:645
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:827
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmmsg+0x27c/0x4a0 net/socket.c:2622
 __do_sys_sendmmsg net/socket.c:2651 [inline]
 __se_sys_sendmmsg net/socket.c:2648 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2648
 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+0x63/0xcd

read-write to 0xffff8881267c9158 of 8 bytes by task 14840 on cpu 0:
 ip_tunnel_xmit+0x10ad/0x16f0 net/ipv4/ip_tunnel.c:822
 sit_tunnel_xmit+0x5a0/0x1410
 __netdev_start_xmit include/linux/netdevice.h:4840 [inline]
 netdev_start_xmit include/linux/netdevice.h:4854 [inline]
 xmit_one+0xc0/0x2a0 net/core/dev.c:3590
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3606
 __dev_queue_xmit+0x84c/0xfe0 net/core/dev.c:4256
 dev_queue_xmit include/linux/netdevice.h:3008 [inline]
 neigh_connected_output+0x266/0x2a0 net/core/neighbour.c:1581
 neigh_output include/net/neighbour.h:546 [inline]
 ip_finish_output2+0x74d/0x850 net/ipv4/ip_output.c:228
 ip_finish_output+0xf3/0x250 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip_output+0xf3/0x1a0 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:445 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb net/ipv4/ip_output.c:1586 [inline]
 ip_push_pending_frames+0xa3/0x120 net/ipv4/ip_output.c:1606
 raw_sendmsg+0xc4f/0xd50 net/ipv4/raw.c:645
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:827
 sock_sendmsg_nosec net/socket.c:714 [inline]
 sock_sendmsg net/socket.c:734 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2482
 ___sys_sendmsg net/socket.c:2536 [inline]
 __sys_sendmmsg+0x27c/0x4a0 net/socket.c:2622
 __do_sys_sendmmsg net/socket.c:2651 [inline]
 __se_sys_sendmmsg net/socket.c:2648 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2648
 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+0x63/0xcd

value changed: 0x0000000000000a79 -> 0x0000000000000a7a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14840 Comm: syz-executor.5 Not tainted 6.1.0-rc3-syzkaller-00280-g64c3dd0b98f5-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
==================================================================