syzbot

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BUG: KCSAN: data-race in ip6_tnl_start_xmit / ip6_tnl_start_xmit

read to 0xffff888132b33168 of 8 bytes by task 5249 on cpu 1:
 ip6_tnl_start_xmit+0x873/0xa90 net/ipv6/ip6_tunnel.c:1438
 __netdev_start_xmit include/linux/netdevice.h:4685 [inline]
 netdev_start_xmit include/linux/netdevice.h:4699 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3473
 dev_hard_start_xmit net/core/dev.c:3489 [inline]
 __dev_queue_xmit+0x86d/0xfa0 net/core/dev.c:4116
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149
 neigh_connected_output+0x264/0x2a0 net/core/neighbour.c:1557
 neigh_output include/net/neighbour.h:549 [inline]
 ip6_finish_output2+0x9ce/0xbe0 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 net/ipv6/ip6_output.c:1915 [inline]
 ip6_push_pending_frames+0xb6/0x170 net/ipv6/ip6_output.c:1935
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x1341/0x14a0 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_sendmmsg+0x267/0x4c0 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+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff888132b33168 of 8 bytes by task 5250 on cpu 0:
 ip6_tnl_start_xmit+0x885/0xa90 net/ipv6/ip6_tunnel.c:1438
 __netdev_start_xmit include/linux/netdevice.h:4685 [inline]
 netdev_start_xmit include/linux/netdevice.h:4699 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3473
 dev_hard_start_xmit net/core/dev.c:3489 [inline]
 __dev_queue_xmit+0x86d/0xfa0 net/core/dev.c:4116
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4149
 neigh_connected_output+0x264/0x2a0 net/core/neighbour.c:1557
 neigh_output include/net/neighbour.h:549 [inline]
 ip6_finish_output2+0x9ce/0xbe0 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 net/ipv6/ip6_output.c:1915 [inline]
 ip6_push_pending_frames+0xb6/0x170 net/ipv6/ip6_output.c:1935
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x1341/0x14a0 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_sendmmsg+0x267/0x4c0 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+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000000002919f -> 0x00000000000291a0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5250 Comm: syz-executor.4 Not tainted 5.17.0-rc7-syzkaller-00205-g79b00034e9dc-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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