IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready ============================================ WARNING: possible recursive locking detected 4.16.0-rc2+ #326 Not tainted -------------------------------------------- syz-executor3/5488 is trying to acquire lock: (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] spin_lock include/linux/spinlock.h:310 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] __netif_tx_lock include/linux/netdevice.h:3561 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready but task is already holding lock: (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] spin_lock include/linux/spinlock.h:310 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] __netif_tx_lock include/linux/netdevice.h:3561 [inline] (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(_xmit_ETHER#2); lock(_xmit_ETHER#2); *** DEADLOCK *** May be due to missing lock nesting notation 12 locks held by syz-executor3/5488: #0: ( IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready sk_lock-AF_INET6){+.+.}, at: [<00000000df5d2aca>] lock_sock include/net/sock.h:1463 [inline] sk_lock-AF_INET6){+.+.}, at: [<00000000df5d2aca>] rawv6_sendmsg+0x1d86/0x40c0 net/ipv6/raw.c:927 #1: (rcu_read_lock){....} IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready , at: [<00000000f66a2eef>] nf_hook include/linux/netfilter.h:206 [inline] , at: [<00000000f66a2eef>] __ip6_local_out+0x2f1/0xaa0 net/ipv6/output_core.c:164 #2: ( IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready rcu_read_lock_bh){....}, at: [<000000001f98d438>] lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] rcu_read_lock_bh){....}, at: [<000000001f98d438>] ip6_finish_output2+0x23d/0x23a0 net/ipv6/ip6_output.c:106 #3: (rcu_read_lock_bh){....}, at: [<00000000d9466217>] __dev_queue_xmit+0x2f6/0x2f30 net/core/dev.c:3483 #4: (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] spin_lock include/linux/spinlock.h:310 [inline] #4: (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] __netif_tx_lock include/linux/netdevice.h:3561 [inline] #4: (_xmit_ETHER#2){+.-.}, at: [<00000000dd957054>] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 #5: (rcu_read_lock){....}, at: [<00000000cedd3c64>] icmpv6_send+0x0/0x280 net/ipv6/ip6_icmp.c:31 #6: (k-slock-AF_INET6){+...}, at: [<00000000847644cc>] spin_trylock include/linux/spinlock.h:320 [inline] #6: (k-slock-AF_INET6){+...}, at: [<00000000847644cc>] icmpv6_xmit_lock net/ipv6/icmp.c:119 [inline] #6: (k-slock-AF_INET6){+...}, at: [<00000000847644cc>] icmp6_send+0x1250/0x2bb0 net/ipv6/icmp.c:528 #7: (rcu_read_lock){....}, at: [<00000000ea1b956d>] icmp6_send+0x1d37/0x2bb0 net/ipv6/icmp.c:563 #8: (rcu_read_lock_bh){....}, at: [<000000001f98d438>] lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #8: (rcu_read_lock_bh){....}, at: [<000000001f98d438>] ip6_finish_output2+0x23d/0x23a0 net/ipv6/ip6_output.c:106 #9: (rcu_read_lock){....}, at: [<00000000766e8d1b>] ip6_nd_hdr net/ipv6/ndisc.c:449 [inline] #9: (rcu_read_lock){....}, at: [<00000000766e8d1b>] ndisc_send_skb+0x826/0x1370 net/ipv6/ndisc.c:485 #10: (rcu_read_lock_bh){....}, at: [<000000001f98d438>] lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline] #10: (rcu_read_lock_bh){....}, at: [<000000001f98d438>] ip6_finish_output2+0x23d/0x23a0 net/ipv6/ip6_output.c:106 #11: (rcu_read_lock_bh){....}, at: [<00000000d9466217>] __dev_queue_xmit+0x2f6/0x2f30 net/core/dev.c:3483 stack backtrace: CPU: 1 PID: 5488 Comm: syz-executor3 Not tainted 4.16.0-rc2+ #326 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_deadlock_bug kernel/locking/lockdep.c:1761 [inline] check_deadlock kernel/locking/lockdep.c:1805 [inline] validate_chain kernel/locking/lockdep.c:2401 [inline] __lock_acquire+0xe8f/0x3e00 kernel/locking/lockdep.c:3431 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144 spin_lock include/linux/spinlock.h:310 [inline] __netif_tx_lock include/linux/netdevice.h:3561 [inline] sch_direct_xmit+0x361/0x1140 net/sched/sch_generic.c:325 qdisc_restart net/sched/sch_generic.c:393 [inline] __qdisc_run+0x57d/0x19c0 net/sched/sch_generic.c:401 __dev_xmit_skb net/core/dev.c:3217 [inline] __dev_queue_xmit+0xd5e/0x2f30 net/core/dev.c:3517 dev_queue_xmit+0x17/0x20 net/core/dev.c:3582 neigh_hh_output include/net/neighbour.h:472 [inline] neigh_output include/net/neighbour.h:480 [inline] ip6_finish_output2+0x1492/0x23a0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x69b/0xaf0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:277 [inline] ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:443 [inline] NF_HOOK include/linux/netfilter.h:288 [inline] ndisc_send_skb+0xac4/0x1370 net/ipv6/ndisc.c:491 ndisc_send_ns+0x38a/0x870 net/ipv6/ndisc.c:633 ndisc_solicit+0x383/0x5c0 net/ipv6/ndisc.c:725 neigh_probe+0xc3/0x100 net/core/neighbour.c:899 __neigh_event_send+0x927/0x1040 net/core/neighbour.c:1055 neigh_event_send include/net/neighbour.h:435 [inline] neigh_resolve_output+0x62b/0xa00 net/core/neighbour.c:1334 neigh_output include/net/neighbour.h:482 [inline] ip6_finish_output2+0xb4a/0x23a0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x69b/0xaf0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:277 [inline] ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:443 [inline] ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697 icmpv6_push_pending_frames+0x338/0x520 net/ipv6/icmp.c:288 icmp6_send+0x2244/0x2bb0 net/ipv6/icmp.c:582 icmpv6_send+0x142/0x280 net/ipv6/ip6_icmp.c:43 ip6_link_failure+0x94/0x570 net/ipv6/route.c:2005 dst_link_failure include/net/dst.h:426 [inline] ip_tunnel_xmit+0x2ada/0x37d0 net/ipv4/ip_tunnel.c:798 __gre_xmit+0x546/0x8b0 net/ipv4/ip_gre.c:449 erspan_xmit+0x779/0x22b0 net/ipv4/ip_gre.c:728 __netdev_start_xmit include/linux/netdevice.h:4066 [inline] netdev_start_xmit include/linux/netdevice.h:4075 [inline] xmit_one net/core/dev.c:3026 [inline] dev_hard_start_xmit+0x24e/0xac0 net/core/dev.c:3042 sch_direct_xmit+0x40d/0x1140 net/sched/sch_generic.c:327 qdisc_restart net/sched/sch_generic.c:393 [inline] __qdisc_run+0x57d/0x19c0 net/sched/sch_generic.c:401 __dev_xmit_skb net/core/dev.c:3217 [inline] __dev_queue_xmit+0xd5e/0x2f30 net/core/dev.c:3517 dev_queue_xmit+0x17/0x20 net/core/dev.c:3582 neigh_resolve_output+0x5e2/0xa00 net/core/neighbour.c:1350 neigh_output include/net/neighbour.h:482 [inline] ip6_finish_output2+0xb4a/0x23a0 net/ipv6/ip6_output.c:120 ip6_finish_output+0x69b/0xaf0 net/ipv6/ip6_output.c:154 NF_HOOK_COND include/linux/netfilter.h:277 [inline] ip6_output+0x1eb/0x840 net/ipv6/ip6_output.c:171 dst_output include/net/dst.h:443 [inline] ip6_local_out+0x95/0x160 net/ipv6/output_core.c:176 nf_dup_ipv6+0x66d/0x8c0 net/ipv6/netfilter/nf_dup_ipv6.c:70 tee_tg6+0x10e/0x170 net/netfilter/xt_TEE.c:48 ip6t_do_table+0xc2a/0x1a30 net/ipv6/netfilter/ip6_tables.c:365 ip6table_raw_hook+0x65/0x80 net/ipv6/netfilter/ip6table_raw.c:42 nf_hook_entry_hookfn include/linux/netfilter.h:120 [inline] nf_hook_slow+0xba/0x1a0 net/netfilter/core.c:483 nf_hook include/linux/netfilter.h:243 [inline] __ip6_local_out+0x517/0xaa0 net/ipv6/output_core.c:164 ip6_local_out+0x2d/0x160 net/ipv6/output_core.c:174 ip6_send_skb+0xa1/0x330 net/ipv6/ip6_output.c:1677 ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1697 rawv6_push_pending_frames net/ipv6/raw.c:616 [inline] rawv6_sendmsg+0x2f96/0x40c0 net/ipv6/raw.c:935 inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:764 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg+0xca/0x110 net/socket.c:640 ___sys_sendmsg+0x767/0x8b0 net/socket.c:2046 __sys_sendmsg+0xe5/0x210 net/socket.c:2080 SYSC_sendmsg net/socket.c:2091 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2087 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x453de9 RSP: 002b:00007fb23a806c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb23a8076d4 RCX: 0000000000453de9 RDX: 0000000000000000 RSI: 000000002001f000 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000004a6 R14: 00000000006f7030 R15: 0000000000000000