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BUG: KCSAN: data-race in ip6_tnl_start_xmit / ip6_tnl_start_xmit

read-write to 0xffff888137653168 of 8 bytes by task 1490 on cpu 1:
 ip6_tnl_start_xmit+0x883/0xa90 net/ipv6/ip6_tunnel.c:1446
 __netdev_start_xmit include/linux/netdevice.h:4775 [inline]
 netdev_start_xmit include/linux/netdevice.h:4789 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3532
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3548
 __dev_queue_xmit+0x84c/0xef0 net/core/dev.c:4176
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4209
 neigh_connected_output+0x264/0x2a0 net/core/neighbour.c:1557
 neigh_output include/net/neighbour.h:549 [inline]
 ip6_finish_output2+0xa00/0xc20 net/ipv6/ip6_output.c:126
 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
 ip6_finish_output+0x446/0x4c0 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:451 [inline]
 ip6_local_out+0x60/0x80 net/ipv6/output_core.c:161
 ip6_send_skb+0x43/0xf0 net/ipv6/ip6_output.c:1925
 udp_v6_send_skb+0x79a/0x9f0 net/ipv6/udp.c:1258
 udpv6_sendmsg+0x138f/0x1440 net/ipv6/udp.c:1550
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:652
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmmsg+0x27c/0x4a0 net/socket.c:2553
 __do_sys_sendmmsg net/socket.c:2582 [inline]
 __se_sys_sendmmsg net/socket.c:2579 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579
 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+0x44/0xae

read-write to 0xffff888137653168 of 8 bytes by task 1481 on cpu 0:
 ip6_tnl_start_xmit+0x883/0xa90 net/ipv6/ip6_tunnel.c:1446
 __netdev_start_xmit include/linux/netdevice.h:4775 [inline]
 netdev_start_xmit include/linux/netdevice.h:4789 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3532
 dev_hard_start_xmit+0x72/0x120 net/core/dev.c:3548
 __dev_queue_xmit+0x84c/0xef0 net/core/dev.c:4176
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4209
 neigh_connected_output+0x264/0x2a0 net/core/neighbour.c:1557
 neigh_output include/net/neighbour.h:549 [inline]
 ip6_finish_output2+0xa00/0xc20 net/ipv6/ip6_output.c:126
 __ip6_finish_output net/ipv6/ip6_output.c:191 [inline]
 ip6_finish_output+0x446/0x4c0 net/ipv6/ip6_output.c:201
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x10e/0x210 net/ipv6/ip6_output.c:224
 dst_output include/net/dst.h:451 [inline]
 ip6_local_out+0x60/0x80 net/ipv6/output_core.c:161
 ip6_send_skb+0x43/0xf0 net/ipv6/ip6_output.c:1925
 udp_v6_send_skb+0x79a/0x9f0 net/ipv6/udp.c:1258
 udpv6_sendmsg+0x138f/0x1440 net/ipv6/udp.c:1550
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:652
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmmsg+0x27c/0x4a0 net/socket.c:2553
 __do_sys_sendmmsg net/socket.c:2582 [inline]
 __se_sys_sendmmsg net/socket.c:2579 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579
 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+0x44/0xae

value changed: 0x000000000000cc8b -> 0x000000000000cc8c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1481 Comm: syz-executor.3 Not tainted 5.18.0-rc6-syzkaller-00007-g9be9ed2612b5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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