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BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit

read to 0xffff88809c035190 of 8 bytes by task 26945 on cpu 0:
 ip_tunnel_xmit+0x1332/0x1450 net/ipv4/ip_tunnel.c:756
 ipip_tunnel_xmit+0x2cb/0x310 net/ipv4/ipip.c:305
 __netdev_start_xmit include/linux/netdevice.h:4447 [inline]
 netdev_start_xmit include/linux/netdevice.h:4461 [inline]
 xmit_one net/core/dev.c:3420 [inline]
 dev_hard_start_xmit+0xef/0x430 net/core/dev.c:3436
 __dev_queue_xmit+0x14e9/0x1ba0 net/core/dev.c:4013
 dev_queue_xmit+0x21/0x30 net/core/dev.c:4046
 neigh_direct_output+0x1f/0x30 net/core/neighbour.c:1530
 neigh_output include/net/neighbour.h:511 [inline]
 ip_finish_output2+0x408/0xea0 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0xfe/0x230 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
 ip_send_skb+0x35/0xb0 net/ipv4/ip_output.c:1562
 udp_send_skb.isra.0+0x3ce/0x8c0 net/ipv4/udp.c:891
 udp_sendmsg+0x1568/0x1900 net/ipv4/udp.c:1178
 udpv6_sendmsg+0xe70/0x1d30 net/ipv6/udp.c:1284
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 ____sys_sendmsg+0x212/0x4d0 net/socket.c:2330
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2384
 __sys_sendmmsg+0x123/0x350 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg net/socket.c:2500 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2500
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88809c035190 of 8 bytes by task 26312 on cpu 1:
 ip_tunnel_xmit+0x1345/0x1450 net/ipv4/ip_tunnel.c:756
 ipip_tunnel_xmit+0x2cb/0x310 net/ipv4/ipip.c:305
 __netdev_start_xmit include/linux/netdevice.h:4447 [inline]
 netdev_start_xmit include/linux/netdevice.h:4461 [inline]
 xmit_one net/core/dev.c:3420 [inline]
 dev_hard_start_xmit+0xef/0x430 net/core/dev.c:3436
 __dev_queue_xmit+0x14e9/0x1ba0 net/core/dev.c:4013
 dev_queue_xmit+0x21/0x30 net/core/dev.c:4046
 neigh_direct_output+0x1f/0x30 net/core/neighbour.c:1530
 neigh_output include/net/neighbour.h:511 [inline]
 ip_finish_output2+0x408/0xea0 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
 ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0xfe/0x230 net/ipv4/ip_output.c:432
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
 ip_send_skb+0x35/0xb0 net/ipv4/ip_output.c:1562
 udp_send_skb.isra.0+0x3ce/0x8c0 net/ipv4/udp.c:891
 udp_sendmsg+0x1568/0x1900 net/ipv4/udp.c:1178
 udpv6_sendmsg+0xe70/0x1d30 net/ipv6/udp.c:1284
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 ____sys_sendmsg+0x212/0x4d0 net/socket.c:2330
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2384
 __sys_sendmmsg+0x123/0x350 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg net/socket.c:2500 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2500
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26312 Comm: syz-executor.3 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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