syzbot

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BUG: KCSAN: data-race in ip6_tnl_start_xmit / ip6_tnl_start_xmit

read to 0xffff888132514168 of 8 bytes by task 6042 on cpu 1:
 ip6_tnl_start_xmit+0x873/0xa90 net/ipv6/ip6_tunnel.c:1438
 __netdev_start_xmit include/linux/netdevice.h:4682 [inline]
 netdev_start_xmit include/linux/netdevice.h:4696 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3473
 dev_hard_start_xmit net/core/dev.c:3489 [inline]
 __dev_queue_xmit+0x86d/0xf90 net/core/dev.c:4116
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149
 neigh_connected_output+0x264/0x2a0 net/core/neighbour.c:1551
 neigh_output include/net/neighbour.h:541 [inline]
 ip6_finish_output2+0x9be/0xbd0 net/ipv6/ip6_output.c:126
 ip6_fragment+0x1197/0x13e0 net/ipv6/ip6_output.c:966
 __ip6_finish_output net/ipv6/ip6_output.c:189 [inline]
 ip6_finish_output+0x465/0x4c0 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 net/ipv6/ip6_output.c:1912 [inline]
 ip6_push_pending_frames+0xb6/0x170 net/ipv6/ip6_output.c:1932
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x132b/0x1400 net/ipv6/raw.c:956
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmsg+0x195/0x230 net/socket.c:2496
 __do_sys_sendmsg net/socket.c:2505 [inline]
 __se_sys_sendmsg net/socket.c:2503 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2503
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff888132514168 of 8 bytes by task 6044 on cpu 0:
 ip6_tnl_start_xmit+0x885/0xa90 net/ipv6/ip6_tunnel.c:1438
 __netdev_start_xmit include/linux/netdevice.h:4682 [inline]
 netdev_start_xmit include/linux/netdevice.h:4696 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3473
 dev_hard_start_xmit net/core/dev.c:3489 [inline]
 __dev_queue_xmit+0x86d/0xf90 net/core/dev.c:4116
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149
 neigh_connected_output+0x264/0x2a0 net/core/neighbour.c:1551
 neigh_output include/net/neighbour.h:541 [inline]
 ip6_finish_output2+0x9be/0xbd0 net/ipv6/ip6_output.c:126
 ip6_fragment+0x1197/0x13e0 net/ipv6/ip6_output.c:966
 __ip6_finish_output net/ipv6/ip6_output.c:189 [inline]
 ip6_finish_output+0x465/0x4c0 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 net/ipv6/ip6_output.c:1912 [inline]
 ip6_push_pending_frames+0xb6/0x170 net/ipv6/ip6_output.c:1932
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x132b/0x1400 net/ipv6/raw.c:956
 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmsg+0x195/0x230 net/socket.c:2496
 __do_sys_sendmsg net/socket.c:2505 [inline]
 __se_sys_sendmsg net/socket.c:2503 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2503
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000000004f4 -> 0x00000000000004f5

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6044 Comm: syz-executor.1 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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