IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready ====================================================== [ INFO: possible circular locking dependency detected ] 4.4.125-g38f41ec #21 Not tainted ------------------------------------------------------- syz-executor4/5770 is trying to acquire lock: (&(&q->lock)->rlock){+.-...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] (&(&q->lock)->rlock){+.-...}, at: [] ip_defrag+0x31d/0x3eb0 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/0x760 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/0x460 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+0x276/0x640 lib/stackdepot.c:252 [] save_stack+0xa3/0xd0 mm/kasan/kasan.c:518 [] set_track mm/kasan/kasan.c:524 [inline] [] kasan_kmalloc+0xad/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+0xba/0x290 mm/slub.c:2628 [] inet_getpeer.part.3+0xec8/0x1560 net/ipv4/inetpeer.c:444 [] inet_getpeer+0x572/0x700 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+0x1787/0x1b70 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+0x4010/0x5020 net/ipv6/reassembly.c:562 [] ip6_input_finish+0x329/0x1540 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+0x106/0x200 net/ipv6/ip6_input.c:280 [] dst_input include/net/dst.h:504 [inline] [] ip6_rcv_finish+0x138/0x630 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+0x1055/0x1e60 net/ipv6/ip6_input.c:186 [] __netif_receive_skb_core+0xa59/0x28f0 net/core/dev.c:4019 [] __netif_receive_skb+0x5b/0x1c0 net/core/dev.c:4054 [] process_backlog+0x213/0x690 net/core/dev.c:4647 [] napi_poll net/core/dev.c:4885 [inline] [] net_rx_action+0x373/0xe70 net/core/dev.c:4950 [] __do_softirq+0x227/0xa38 kernel/softirq.c:273 [] do_softirq_own_stack+0x1c/0x30 arch/x86/entry/entry_64.S:929 [] do_softirq.part.17+0x54/0x60 kernel/softirq.c:317 [] do_softirq+0x19/0x20 kernel/softirq.c:320 [] netif_rx_ni+0x166/0x3a0 net/core/dev.c:3653 [] tun_get_user+0xc74/0x2340 drivers/net/tun.c:1264 [] tun_chr_write_iter+0xd5/0x190 drivers/net/tun.c:1283 [] do_iter_readv_writev+0x138/0x1e0 fs/read_write.c:664 [] compat_do_readv_writev+0x2d4/0x6e0 fs/read_write.c:982 [] compat_writev+0xdc/0x150 fs/read_write.c:1090 [] C_SYSC_writev fs/read_write.c:1110 [inline] [] compat_SyS_writev+0xd8/0x1b0 fs/read_write.c:1099 [] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline] [] do_fast_syscall_32+0x321/0x8a0 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+0x371f/0x4b50 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x460 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+0x31d/0x3eb0 net/ipv4/ip_fragment.c:680 [] ip_check_defrag+0x383/0x770 net/ipv4/ip_fragment.c:724 [] packet_rcv_fanout+0x192/0x620 net/packet/af_packet.c:1451 [] dev_queue_xmit_nit net/core/dev.c:1913 [inline] [] xmit_one net/core/dev.c:2755 [inline] [] dev_hard_start_xmit+0x62b/0x1220 net/core/dev.c:2775 [] sch_direct_xmit+0x2c1/0x760 net/sched/sch_generic.c:165 [] __dev_xmit_skb net/core/dev.c:2957 [inline] [] __dev_queue_xmit+0x148e/0x1cc0 net/core/dev.c:3175 [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3241 [] neigh_resolve_output+0x469/0x770 net/core/neighbour.c:1312 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip_finish_output2+0x6f4/0x10b0 net/ipv4/ip_output.c:213 [] ip_do_fragment+0xcbf/0x2120 net/ipv4/ip_output.c:633 [] ip_fragment.constprop.49+0x145/0x200 net/ipv4/ip_output.c:503 [] ip_finish_output+0x50b/0xb00 net/ipv4/ip_output.c:286 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip_mc_output+0x237/0x980 net/ipv4/ip_output.c:347 [] dst_output include/net/dst.h:498 [inline] [] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:119 [] ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1450 [] udp_send_skb+0x66c/0xcd0 net/ipv4/udp.c:842 [] udp_sendmsg+0x981/0x1c30 net/ipv4/udp.c:1070 [] inet_sendmsg+0x2bc/0x4c0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:625 [inline] [] sock_sendmsg+0xca/0x110 net/socket.c:635 [] SYSC_sendto+0x2c8/0x340 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+0x321/0x8a0 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-executor4/5770: #0: (rcu_read_lock_bh){......}, at: [] ip_finish_output2+0x203/0x10b0 net/ipv4/ip_output.c:193 #1: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x1d5/0x1cc0 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/0x760 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+0xa6/0x1220 net/core/dev.c:2775 stack backtrace: CPU: 0 PID: 5770 Comm: syz-executor4 Not tainted 4.4.125-g38f41ec #21 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 37f724ec4b85a5dd ffff8801c7a16cc8 ffffffff81d067bd ffffffff851c02b0 ffffffff851c02b0 ffffffff851bee70 ffff8801d91fe980 ffff8801d91fe000 ffff8801c7a16d10 ffffffff81234081 ffff8801d91fe980 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x124 lib/dump_stack.c:51 [] print_circular_bug+0x271/0x310 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+0x371f/0x4b50 kernel/locking/lockdep.c:3213 [] lock_acquire+0x15e/0x460 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+0x31d/0x3eb0 net/ipv4/ip_fragment.c:680 [] ip_check_defrag+0x383/0x770 net/ipv4/ip_fragment.c:724 [] packet_rcv_fanout+0x192/0x620 net/packet/af_packet.c:1451 [] dev_queue_xmit_nit net/core/dev.c:1913 [inline] [] xmit_one net/core/dev.c:2755 [inline] [] dev_hard_start_xmit+0x62b/0x1220 net/core/dev.c:2775 [] sch_direct_xmit+0x2c1/0x760 net/sched/sch_generic.c:165 [] __dev_xmit_skb net/core/dev.c:2957 [inline] [] __dev_queue_xmit+0x148e/0x1cc0 net/core/dev.c:3175 [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3241 [] neigh_resolve_output+0x469/0x770 net/core/neighbour.c:1312 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip_finish_output2+0x6f4/0x10b0 net/ipv4/ip_output.c:213 [] ip_do_fragment+0xcbf/0x2120 net/ipv4/ip_output.c:633 [] ip_fragment.constprop.49+0x145/0x200 net/ipv4/ip_output.c:503 [] ip_finish_output+0x50b/0xb00 net/ipv4/ip_output.c:286 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip_mc_output+0x237/0x980 net/ipv4/ip_output.c:347 [] dst_output include/net/dst.h:498 [inline] [] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:119 [] ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1450 [] udp_send_skb+0x66c/0xcd0 net/ipv4/udp.c:842 [] udp_sendmsg+0x981/0x1c30 net/ipv4/udp.c:1070 [] inet_sendmsg+0x2bc/0x4c0 net/ipv4/af_inet.c:755 [] sock_sendmsg_nosec net/socket.c:625 [inline] [] sock_sendmsg+0xca/0x110 net/socket.c:635 [] SYSC_sendto+0x2c8/0x340 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+0x321/0x8a0 arch/x86/entry/common.c:459 [] sysenter_flags_fixed+0xd/0x17