================================================================== BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit write to 0xffff88812ae17170 of 8 bytes by task 28153 on cpu 1: ip_tunnel_xmit+0x918/0x11b0 net/ipv4/ip_tunnel.c:762 sit_tunnel_xmit__ net/ipv6/sit.c:1065 [inline] sit_tunnel_xmit+0x3d3/0x1200 net/ipv6/sit.c:1081 __netdev_start_xmit include/linux/netdevice.h:4988 [inline] netdev_start_xmit include/linux/netdevice.h:5002 [inline] xmit_one+0xf9/0x270 net/core/dev.c:3576 dev_hard_start_xmit net/core/dev.c:3592 [inline] __dev_queue_xmit+0x6e9/0xaa0 net/core/dev.c:4202 dev_queue_xmit+0x13/0x20 net/core/dev.c:4235 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1521 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x80a/0xaa0 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_output+0xf3/0x1a0 net/ipv4/ip_output.c:423 dst_output include/net/dst.h:450 [inline] ip_local_out+0x164/0x220 net/ipv4/ip_output.c:126 ip_send_skb+0x27/0x90 net/ipv4/ip_output.c:1555 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:966 udp_sendmsg+0x1257/0x1320 net/ipv4/udp.c:1253 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:821 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+0x388/0x520 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 0xffff88812ae17170 of 8 bytes by task 28141 on cpu 0: ip_tunnel_xmit+0x906/0x11b0 net/ipv4/ip_tunnel.c:762 sit_tunnel_xmit__ net/ipv6/sit.c:1065 [inline] sit_tunnel_xmit+0x3d3/0x1200 net/ipv6/sit.c:1081 __netdev_start_xmit include/linux/netdevice.h:4988 [inline] netdev_start_xmit include/linux/netdevice.h:5002 [inline] xmit_one+0xf9/0x270 net/core/dev.c:3576 dev_hard_start_xmit net/core/dev.c:3592 [inline] __dev_queue_xmit+0x6e9/0xaa0 net/core/dev.c:4202 dev_queue_xmit+0x13/0x20 net/core/dev.c:4235 neigh_connected_output+0x264/0x290 net/core/neighbour.c:1521 neigh_output include/net/neighbour.h:510 [inline] ip_finish_output2+0x80a/0xaa0 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_output+0xf3/0x1a0 net/ipv4/ip_output.c:423 dst_output include/net/dst.h:450 [inline] ip_local_out+0x164/0x220 net/ipv4/ip_output.c:126 ip_send_skb+0x27/0x90 net/ipv4/ip_output.c:1555 udp_send_skb+0x62d/0x860 net/ipv4/udp.c:966 udp_sendmsg+0x1257/0x1320 net/ipv4/udp.c:1253 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:821 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+0x388/0x520 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: 0x000000000000aaf7 -> 0x000000000000aaf8 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 28141 Comm: syz-executor.5 Tainted: G W 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================