syzbot

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BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

read-write to 0xffff888138efd1b8 of 8 bytes by task 21872 on cpu 0:
 ip_tunnel_xmit+0x7d1/0x16e0 net/ipv4/ip_tunnel.c:751
 ipip_tunnel_xmit+0x252/0x2b0 net/ipv4/ipip.c:307
 __netdev_start_xmit include/linux/netdevice.h:4805 [inline]
 netdev_start_xmit include/linux/netdevice.h:4819 [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:2994 [inline]
 neigh_connected_output+0x266/0x2a0 net/core/neighbour.c:1557
 neigh_output include/net/neighbour.h:550 [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:296 [inline]
 ip_output+0xf3/0x1a0 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:451 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1589
 udp_send_skb+0x626/0x860 net/ipv4/udp.c:969
 udp_sendmsg+0x114b/0x1200 net/ipv4/udp.c:1256
 udpv6_sendmsg+0x64e/0x14a0
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:653
 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 0xffff888138efd1b8 of 8 bytes by task 21858 on cpu 1:
 ip_tunnel_xmit+0x7d1/0x16e0 net/ipv4/ip_tunnel.c:751
 ipip_tunnel_xmit+0x252/0x2b0 net/ipv4/ipip.c:307
 __netdev_start_xmit include/linux/netdevice.h:4805 [inline]
 netdev_start_xmit include/linux/netdevice.h:4819 [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:2994 [inline]
 neigh_connected_output+0x266/0x2a0 net/core/neighbour.c:1557
 neigh_output include/net/neighbour.h:550 [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:296 [inline]
 ip_output+0xf3/0x1a0 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:451 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1589
 udp_send_skb+0x626/0x860 net/ipv4/udp.c:969
 udp_sendmsg+0x114b/0x1200 net/ipv4/udp.c:1256
 udpv6_sendmsg+0x64e/0x14a0
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:653
 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: 0x000000000000815c -> 0x000000000000815d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21858 Comm: syz-executor.1 Not tainted 5.19.0-syzkaller-13930-g7ebfc85e2cd7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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syz-executor.1 (21858) used greatest stack depth: 10184 bytes left