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BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

write to 0xffff88812ebfb150 of 8 bytes by task 18985 on cpu 0:
 ip_tunnel_xmit+0x9fe/0x1210 net/ipv4/ip_tunnel.c:819
 sit_tunnel_xmit__ net/ipv6/sit.c:1065 [inline]
 sit_tunnel_xmit+0x3d3/0x1210 net/ipv6/sit.c:1081
 __netdev_start_xmit include/linux/netdevice.h:4987 [inline]
 netdev_start_xmit include/linux/netdevice.h:5001 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3590
 dev_hard_start_xmit net/core/dev.c:3606 [inline]
 __dev_queue_xmit+0x6fc/0xe00 net/core/dev.c:4226
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4259
 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1552
 neigh_output include/net/neighbour.h:527 [inline]
 ip_finish_output2+0x6c4/0xad0 net/ipv4/ip_output.c:221
 ip_finish_output+0x3b5/0x510 net/ipv4/ip_output.c:309
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_mc_output+0x2a7/0x360 net/ipv4/ip_output.c:408
 dst_output include/net/dst.h:450 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1555
 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:966
 udp_sendmsg+0x1273/0x1340 net/ipv4/udp.c:1253
 udpv6_sendmsg+0x6a3/0x16e0
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:644
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2409
 ___sys_sendmsg net/socket.c:2463 [inline]
 __sys_sendmmsg+0x267/0x4c0 net/socket.c:2549
 __do_sys_sendmmsg net/socket.c:2578 [inline]
 __se_sys_sendmmsg net/socket.c:2575 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2575
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812ebfb150 of 8 bytes by task 18672 on cpu 1:
 ip_tunnel_xmit+0x9ec/0x1210 net/ipv4/ip_tunnel.c:819
 sit_tunnel_xmit__ net/ipv6/sit.c:1065 [inline]
 sit_tunnel_xmit+0x3d3/0x1210 net/ipv6/sit.c:1081
 __netdev_start_xmit include/linux/netdevice.h:4987 [inline]
 netdev_start_xmit include/linux/netdevice.h:5001 [inline]
 xmit_one+0x105/0x2f0 net/core/dev.c:3590
 dev_hard_start_xmit net/core/dev.c:3606 [inline]
 __dev_queue_xmit+0x6fc/0xe00 net/core/dev.c:4226
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4259
 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1552
 neigh_output include/net/neighbour.h:527 [inline]
 ip_finish_output2+0x6c4/0xad0 net/ipv4/ip_output.c:221
 ip_finish_output+0x3b5/0x510 net/ipv4/ip_output.c:309
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_mc_output+0x2a7/0x360 net/ipv4/ip_output.c:408
 dst_output include/net/dst.h:450 [inline]
 ip_local_out net/ipv4/ip_output.c:126 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1555
 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:966
 udp_sendmsg+0x1273/0x1340 net/ipv4/udp.c:1253
 udpv6_sendmsg+0x6a3/0x16e0
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:644
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg net/socket.c:724 [inline]
 ____sys_sendmsg+0x39a/0x510 net/socket.c:2409
 ___sys_sendmsg net/socket.c:2463 [inline]
 __sys_sendmmsg+0x267/0x4c0 net/socket.c:2549
 __do_sys_sendmmsg net/socket.c:2578 [inline]
 __se_sys_sendmmsg net/socket.c:2575 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2575
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000417 -> 0x0000000000000418

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18672 Comm: syz-executor.0 Tainted: G        W         5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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