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BUG: KCSAN: data-race in vti_tunnel_xmit / vti_tunnel_xmit

write to 0xffff88802a347150 of 8 bytes by task 7174 on cpu 1:
 vti_xmit net/ipv4/ip_vti.c:268 [inline]
 vti_tunnel_xmit+0x842/0xa90 net/ipv4/ip_vti.c:302
 __netdev_start_xmit include/linux/netdevice.h:4823 [inline]
 netdev_start_xmit include/linux/netdevice.h:4837 [inline]
 xmit_one+0xf9/0x2e0 net/core/dev.c:3593
 dev_hard_start_xmit net/core/dev.c:3609 [inline]
 __dev_queue_xmit+0xf22/0x1580 net/core/dev.c:4182
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4215
 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1520
 neigh_output include/net/neighbour.h:510 [inline]
 ip6_finish_output2+0x985/0xb20 net/ipv6/ip6_output.c:117
 __ip6_finish_output+0x428/0x480 net/ipv6/ip6_output.c:182
 ip6_finish_output+0x39/0x160 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:215
 dst_output include/net/dst.h:448 [inline]
 ip6_local_out+0x60/0x80 net/ipv6/output_core.c:179
 ip6_send_skb+0x43/0xf0 net/ipv6/ip6_output.c:1904
 udp_v6_send_skb+0x798/0x9f0 net/ipv6/udp.c:1234
 udpv6_sendmsg+0x152f/0x1790 net/ipv6/udp.c:1532
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:642
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmmsg+0x315/0x4b0 net/socket.c:2490
 __do_sys_sendmmsg net/socket.c:2519 [inline]
 __se_sys_sendmmsg net/socket.c:2516 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88802a347150 of 8 bytes by task 7183 on cpu 0:
 vti_xmit net/ipv4/ip_vti.c:268 [inline]
 vti_tunnel_xmit+0x830/0xa90 net/ipv4/ip_vti.c:302
 __netdev_start_xmit include/linux/netdevice.h:4823 [inline]
 netdev_start_xmit include/linux/netdevice.h:4837 [inline]
 xmit_one+0xf9/0x2e0 net/core/dev.c:3593
 dev_hard_start_xmit net/core/dev.c:3609 [inline]
 __dev_queue_xmit+0xf22/0x1580 net/core/dev.c:4182
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4215
 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1520
 neigh_output include/net/neighbour.h:510 [inline]
 ip6_finish_output2+0x985/0xb20 net/ipv6/ip6_output.c:117
 __ip6_finish_output+0x428/0x480 net/ipv6/ip6_output.c:182
 ip6_finish_output+0x39/0x160 net/ipv6/ip6_output.c:192
 NF_HOOK_COND include/linux/netfilter.h:290 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:215
 dst_output include/net/dst.h:448 [inline]
 ip6_local_out+0x60/0x80 net/ipv6/output_core.c:179
 ip6_send_skb+0x43/0xf0 net/ipv6/ip6_output.c:1904
 udp_v6_send_skb+0x798/0x9f0 net/ipv6/udp.c:1234
 udpv6_sendmsg+0x152f/0x1790 net/ipv6/udp.c:1532
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:642
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmmsg+0x315/0x4b0 net/socket.c:2490
 __do_sys_sendmmsg net/socket.c:2519 [inline]
 __se_sys_sendmmsg net/socket.c:2516 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7183 Comm: syz-executor.1 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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