================================================================== BUG: KCSAN: data-race in ip_tunnel_xmit / ip_tunnel_xmit write to 0xffff8881396ef0e4 of 2 bytes by task 3224 on cpu 1: ip_tunnel_xmit+0x1294/0x1730 net/ipv4/ip_tunnel.c:804 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661 __netdev_start_xmit include/linux/netdevice.h:4863 [inline] netdev_start_xmit include/linux/netdevice.h:4877 [inline] xmit_one net/core/dev.c:3575 [inline] dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3591 __dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4241 dev_queue_xmit include/linux/netdevice.h:3033 [inline] neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623 neigh_output include/net/neighbour.h:546 [inline] ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228 ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:444 [inline] ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126 iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661 __netdev_start_xmit include/linux/netdevice.h:4863 [inline] netdev_start_xmit include/linux/netdevice.h:4877 [inline] xmit_one net/core/dev.c:3575 [inline] dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3591 __dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4241 dev_queue_xmit include/linux/netdevice.h:3033 [inline] neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623 neigh_output include/net/neighbour.h:546 [inline] ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228 ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:444 [inline] ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126 iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661 __netdev_start_xmit include/linux/netdevice.h:4863 [inline] netdev_start_xmit include/linux/netdevice.h:4877 [inline] xmit_one net/core/dev.c:3575 [inline] dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3591 __dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4241 dev_queue_xmit include/linux/netdevice.h:3033 [inline] neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623 neigh_output include/net/neighbour.h:546 [inline] ip6_finish_output2+0x9bc/0xc50 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline] ip6_finish_output+0x39a/0x4e0 net/ipv6/ip6_output.c:206 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0xeb/0x220 net/ipv6/ip6_output.c:227 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] mld_sendpack+0x438/0x6a0 net/ipv6/mcast.c:1820 mld_send_cr net/ipv6/mcast.c:2121 [inline] mld_ifc_work+0x52c/0x7c0 net/ipv6/mcast.c:2653 process_one_work+0x3e6/0x750 kernel/workqueue.c:2289 worker_thread+0x5ef/0xa10 kernel/workqueue.c:2436 kthread+0x1ac/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 read to 0xffff8881396ef0e4 of 2 bytes by task 883 on cpu 0: ip_tunnel_xmit+0x1270/0x1730 net/ipv4/ip_tunnel.c:803 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661 __netdev_start_xmit include/linux/netdevice.h:4863 [inline] netdev_start_xmit include/linux/netdevice.h:4877 [inline] xmit_one net/core/dev.c:3575 [inline] dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3591 __dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4241 dev_queue_xmit include/linux/netdevice.h:3033 [inline] neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623 neigh_output include/net/neighbour.h:546 [inline] ip_finish_output2+0x740/0x840 net/ipv4/ip_output.c:228 ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:444 [inline] ip_local_out+0x64/0x80 net/ipv4/ip_output.c:126 iptunnel_xmit+0x34a/0x4b0 net/ipv4/ip_tunnel_core.c:82 ip_tunnel_xmit+0x1451/0x1730 net/ipv4/ip_tunnel.c:813 __gre_xmit net/ipv4/ip_gre.c:469 [inline] ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:661 __netdev_start_xmit include/linux/netdevice.h:4863 [inline] netdev_start_xmit include/linux/netdevice.h:4877 [inline] xmit_one net/core/dev.c:3575 [inline] dev_hard_start_xmit+0x127/0x400 net/core/dev.c:3591 __dev_queue_xmit+0x1007/0x1eb0 net/core/dev.c:4241 dev_queue_xmit include/linux/netdevice.h:3033 [inline] neigh_direct_output+0x17/0x20 net/core/neighbour.c:1623 neigh_output include/net/neighbour.h:546 [inline] ip6_finish_output2+0x9bc/0xc50 net/ipv6/ip6_output.c:134 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline] ip6_finish_output+0x39a/0x4e0 net/ipv6/ip6_output.c:206 NF_HOOK_COND include/linux/netfilter.h:291 [inline] ip6_output+0xeb/0x220 net/ipv6/ip6_output.c:227 dst_output include/net/dst.h:444 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] mld_sendpack+0x438/0x6a0 net/ipv6/mcast.c:1820 mld_send_cr net/ipv6/mcast.c:2121 [inline] mld_ifc_work+0x52c/0x7c0 net/ipv6/mcast.c:2653 process_one_work+0x3e6/0x750 kernel/workqueue.c:2289 worker_thread+0x5ef/0xa10 kernel/workqueue.c:2436 kthread+0x1ac/0x1e0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 value changed: 0x1bd4 -> 0x1c14 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 883 Comm: kworker/0:2 Not tainted 6.2.0-syzkaller-02172-g9e58df973d22-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023 Workqueue: mld mld_ifc_work ==================================================================