IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready ====================================================== [ INFO: possible circular locking dependency detected ] 4.4.137-ga2e2217 #59 Not tainted ------------------------------------------------------- syz-executor0/4060 is trying to acquire lock: (&(&q->lock)->rlock){+.-...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] (&(&q->lock)->rlock){+.-...}, at: [] ip_defrag+0x318/0x3fe0 net/ipv4/ip_fragment.c:680 but task is already holding lock: (_xmit_NETROM){+.-...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] (_xmit_NETROM){+.-...}, at: [] __netif_tx_lock include/linux/netdevice.h:3299 [inline] (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 net/sched/sch_generic.c:163 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:112 [inline] [] _raw_spin_lock_irqsave+0x4e/0x70 kernel/locking/spinlock.c:159 [] depot_save_stack+0x211/0x610 lib/stackdepot.c:252 [] save_stack+0xa9/0xd0 mm/kasan/kasan.c:518 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616 [] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554 [] slab_post_alloc_hook mm/slub.c:1349 [inline] [] slab_alloc_node mm/slub.c:2615 [inline] [] slab_alloc mm/slub.c:2623 [inline] [] kmem_cache_alloc+0xbe/0x2a0 mm/slub.c:2628 [] inet_getpeer.part.5+0xeac/0x15a0 net/ipv4/inetpeer.c:444 [] inet_getpeer+0x55b/0x6f0 include/linux/seqlock.h:374 [] inet_getpeer_v6 include/net/inetpeer.h:127 [inline] [] icmpv6_xrlim_allow net/ipv6/icmp.c:211 [inline] [] icmp6_send+0x17c5/0x1b80 net/ipv6/icmp.c:491 [] icmpv6_param_prob+0x29/0x40 net/ipv6/icmp.c:551 [] ip6_frag_queue net/ipv6/reassembly.c:263 [inline] [] ipv6_frag_rcv+0x3f94/0x4fd0 net/ipv6/reassembly.c:562 [] ip6_input_finish+0x32e/0x1550 net/ipv6/ip6_input.c:248 [] NF_HOOK_THRESH include/linux/netfilter.h:226 [inline] [] NF_HOOK include/linux/netfilter.h:249 [inline] [] ip6_input+0xf6/0x200 net/ipv6/ip6_input.c:280 [] dst_input include/net/dst.h:504 [inline] [] ip6_rcv_finish+0x13d/0x640 net/ipv6/ip6_input.c:62 [] NF_HOOK_THRESH include/linux/netfilter.h:226 [inline] [] NF_HOOK include/linux/netfilter.h:249 [inline] [] ipv6_rcv+0x10cb/0x1cd0 net/ipv6/ip6_input.c:186 [] __netif_receive_skb_core+0x12d6/0x2940 net/core/dev.c:4019 [] __netif_receive_skb+0x5b/0x1b0 net/core/dev.c:4054 [] process_backlog+0x216/0x6a0 net/core/dev.c:4647 [] napi_poll net/core/dev.c:4885 [inline] [] net_rx_action+0x3a2/0xdb0 net/core/dev.c:4950 [] __do_softirq+0x22c/0xa1a kernel/softirq.c:273 [] do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:929 [] do_softirq.part.16+0x54/0x60 kernel/softirq.c:317 [] do_softirq+0x19/0x20 kernel/softirq.c:320 [] netif_rx_ni+0xec/0x3a0 net/core/dev.c:3653 [] tun_get_user+0xbe7/0x2410 drivers/net/tun.c:1264 [] tun_chr_write_iter+0xd5/0x190 drivers/net/tun.c:1283 [] do_iter_readv_writev+0x13c/0x1e0 fs/read_write.c:664 [] compat_do_readv_writev+0x2e2/0x6e0 fs/read_write.c:982 [] compat_writev+0xe1/0x150 fs/read_write.c:1090 [] C_SYSC_writev fs/read_write.c:1110 [inline] [] compat_SyS_writev+0xd8/0x1c0 fs/read_write.c:1099 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x3902/0x5270 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline] [] _raw_spin_lock+0x36/0x50 kernel/locking/spinlock.c:151 [] spin_lock include/linux/spinlock.h:302 [inline] [] ip_defrag+0x318/0x3fe0 net/ipv4/ip_fragment.c:680 [] ip_check_defrag+0x3c8/0x7e0 net/ipv4/ip_fragment.c:724 [] packet_rcv_fanout+0x52a/0x5e0 net/packet/af_packet.c:1458 [] dev_queue_xmit_nit net/core/dev.c:1913 [inline] [] xmit_one net/core/dev.c:2755 [inline] [] dev_hard_start_xmit+0x644/0x11c0 net/core/dev.c:2775 [] sch_direct_xmit+0x2c1/0x6e0 net/sched/sch_generic.c:165 [] __dev_xmit_skb net/core/dev.c:2957 [inline] [] __dev_queue_xmit+0xef3/0x1c80 net/core/dev.c:3175 [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3241 [] neigh_resolve_output+0x637/0x790 net/core/neighbour.c:1326 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip_finish_output2+0x6ab/0x1110 net/ipv4/ip_output.c:213 [] ip_do_fragment+0x19cc/0x2190 net/ipv4/ip_output.c:633 [] ip_fragment.constprop.51+0x143/0x200 net/ipv4/ip_output.c:503 [] ip_finish_output+0x48a/0xc00 net/ipv4/ip_output.c:286 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip_mc_output+0x233/0x980 net/ipv4/ip_output.c:347 [] dst_output include/net/dst.h:498 [inline] [] ip_local_out+0x9b/0x180 net/ipv4/ip_output.c:119 [] ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1451 [] udp_send_skb+0x5c3/0xc60 net/ipv4/udp.c:842 [] udp_sendmsg+0x16c9/0x1c70 net/ipv4/udp.c:1072 [] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:625 [inline] [] sock_sendmsg+0xcc/0x110 net/socket.c:635 [] SYSC_sendto+0x21c/0x370 net/socket.c:1665 [] SyS_sendto+0x40/0x50 net/socket.c:1633 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(_xmit_NETROM); lock(&(&q->lock)->rlock); lock(_xmit_NETROM); lock(&(&q->lock)->rlock); *** DEADLOCK *** 4 locks held by syz-executor0/4060: #0: (rcu_read_lock_bh){......}, at: [] ip_finish_output2+0x212/0x1110 net/ipv4/ip_output.c:193 #1: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x1d7/0x1c80 net/core/dev.c:3139 #2: (_xmit_NETROM){+.-...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] #2: (_xmit_NETROM){+.-...}, at: [] __netif_tx_lock include/linux/netdevice.h:3299 [inline] #2: (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 net/sched/sch_generic.c:163 #3: (rcu_read_lock){......}, at: [] xmit_one net/core/dev.c:2754 [inline] #3: (rcu_read_lock){......}, at: [] dev_hard_start_xmit+0xa8/0x11c0 net/core/dev.c:2775 stack backtrace: CPU: 1 PID: 4060 Comm: syz-executor0 Not tainted 4.4.137-ga2e2217 #59 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 54302b7d1e45a49a ffff8801d96becc8 ffffffff81e0ee0d ffffffff853ed070 ffffffff853ebc30 ffffffff853ed070 ffff8800bac68950 ffff8800bac68000 ffff8801d96bed10 ffffffff8140e6ab 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_circular_bug.cold.50+0x1bd/0x27d kernel/locking/lockdep.c:1226 [] check_prev_add kernel/locking/lockdep.c:1853 [inline] [] check_prevs_add kernel/locking/lockdep.c:1958 [inline] [] validate_chain kernel/locking/lockdep.c:2144 [inline] [] __lock_acquire+0x3902/0x5270 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592 [] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline] [] _raw_spin_lock+0x36/0x50 kernel/locking/spinlock.c:151 [] spin_lock include/linux/spinlock.h:302 [inline] [] ip_defrag+0x318/0x3fe0 net/ipv4/ip_fragment.c:680 [] ip_check_defrag+0x3c8/0x7e0 net/ipv4/ip_fragment.c:724 [] packet_rcv_fanout+0x52a/0x5e0 net/packet/af_packet.c:1458 [] dev_queue_xmit_nit net/core/dev.c:1913 [inline] [] xmit_one net/core/dev.c:2755 [inline] [] dev_hard_start_xmit+0x644/0x11c0 net/core/dev.c:2775 [] sch_direct_xmit+0x2c1/0x6e0 net/sched/sch_generic.c:165 [] __dev_xmit_skb net/core/dev.c:2957 [inline] [] __dev_queue_xmit+0xef3/0x1c80 net/core/dev.c:3175 [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3241 [] neigh_resolve_output+0x637/0x790 net/core/neighbour.c:1326 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip_finish_output2+0x6ab/0x1110 net/ipv4/ip_output.c:213 [] ip_do_fragment+0x19cc/0x2190 net/ipv4/ip_output.c:633 [] ip_fragment.constprop.51+0x143/0x200 net/ipv4/ip_output.c:503 [] ip_finish_output+0x48a/0xc00 net/ipv4/ip_output.c:286 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip_mc_output+0x233/0x980 net/ipv4/ip_output.c:347 [] dst_output include/net/dst.h:498 [inline] [] ip_local_out+0x9b/0x180 net/ipv4/ip_output.c:119 [] ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1451 [] udp_send_skb+0x5c3/0xc60 net/ipv4/udp.c:842 [] udp_sendmsg+0x16c9/0x1c70 net/ipv4/udp.c:1072 [] inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:625 [inline] [] sock_sendmsg+0xcc/0x110 net/socket.c:635 [] SYSC_sendto+0x21c/0x370 net/socket.c:1665