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BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

write to 0xffff88810d1ff130 of 8 bytes by task 26179 on cpu 1:
 ip_tunnel_xmit+0xb28/0x11c0 net/ipv4/ip_tunnel.c:825
 ipip_tunnel_xmit+0x264/0x2c0 net/ipv4/ipip.c:305
 __netdev_start_xmit include/linux/netdevice.h:4611 [inline]
 netdev_start_xmit include/linux/netdevice.h:4625 [inline]
 xmit_one+0xc0/0x310 net/core/dev.c:3556
 dev_hard_start_xmit net/core/dev.c:3572 [inline]
 __dev_queue_xmit+0xecc/0x1550 net/core/dev.c:4131
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4164
 neigh_direct_output+0x11/0x20 net/core/neighbour.c:1529
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x4e2/0xb60 net/ipv4/ip_output.c:228
 __ip_finish_output+0x395/0x3e0 net/ipv4/ip_output.c:306
 ip_finish_output+0x39/0x160 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0xf6/0x1a0 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:435 [inline]
 ip_local_out net/ipv4/ip_output.c:125 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1560
 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:894
 udp_sendmsg+0x126e/0x1510 net/ipv4/udp.c:1181
 udpv6_sendmsg+0x94b/0x1770 net/ipv6/udp.c:1286
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:638
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmmsg+0x322/0x4b0 net/socket.c:2496
 __do_sys_sendmmsg net/socket.c:2525 [inline]
 __se_sys_sendmmsg net/socket.c:2522 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2522
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810d1ff130 of 8 bytes by task 26181 on cpu 0:
 ip_tunnel_xmit+0xb16/0x11c0 net/ipv4/ip_tunnel.c:825
 ipip_tunnel_xmit+0x264/0x2c0 net/ipv4/ipip.c:305
 __netdev_start_xmit include/linux/netdevice.h:4611 [inline]
 netdev_start_xmit include/linux/netdevice.h:4625 [inline]
 xmit_one+0xc0/0x310 net/core/dev.c:3556
 dev_hard_start_xmit net/core/dev.c:3572 [inline]
 __dev_queue_xmit+0xecc/0x1550 net/core/dev.c:4131
 dev_queue_xmit+0x13/0x20 net/core/dev.c:4164
 neigh_direct_output+0x11/0x20 net/core/neighbour.c:1529
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x4e2/0xb60 net/ipv4/ip_output.c:228
 __ip_finish_output+0x395/0x3e0 net/ipv4/ip_output.c:306
 ip_finish_output+0x39/0x160 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0xf6/0x1a0 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:435 [inline]
 ip_local_out net/ipv4/ip_output.c:125 [inline]
 ip_send_skb+0x6e/0xe0 net/ipv4/ip_output.c:1560
 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:894
 udp_sendmsg+0x126e/0x1510 net/ipv4/udp.c:1181
 udpv6_sendmsg+0x94b/0x1770 net/ipv6/udp.c:1286
 inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:638
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg net/socket.c:672 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2352
 ___sys_sendmsg net/socket.c:2406 [inline]
 __sys_sendmmsg+0x322/0x4b0 net/socket.c:2496
 __do_sys_sendmmsg net/socket.c:2525 [inline]
 __se_sys_sendmmsg net/socket.c:2522 [inline]
 __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2522
 do_syscall_64+0x71/0x120 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26181 Comm: syz-executor.0 Not tainted 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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