netlink: 328 bytes leftover after parsing attributes in process `syz-executor2'. netlink: 328 bytes leftover after parsing attributes in process `syz-executor2'. ====================================================== [ INFO: possible circular locking dependency detected ] 4.4.125-g38f41ec #21 Not tainted ------------------------------------------------------- syz-executor1/12601 is trying to acquire 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 but task is already holding lock: (&(&q->lock)->rlock#2){+.-...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] (&(&q->lock)->rlock#2){+.-...}, at: [] ipv6_frag_rcv+0x5e7/0x5020 net/ipv6/reassembly.c:560 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 [] try_to_wake_up+0x2c/0xf60 kernel/sched/core.c:1974 [] wake_up_q+0xbe/0x130 kernel/sched/core.c:582 [] __mutex_unlock_common_slowpath kernel/locking/mutex.c:754 [inline] [] __mutex_unlock_slowpath+0x208/0x3b0 kernel/locking/mutex.c:765 [] mutex_unlock+0x9/0x10 kernel/locking/mutex.c:437 [] ptmx_open+0x102/0x320 drivers/tty/pty.c:770 [] chrdev_open+0x22b/0x4c0 fs/char_dev.c:388 [] do_dentry_open+0x59b/0xba0 fs/open.c:749 [] vfs_open+0x110/0x210 fs/open.c:862 [] do_last fs/namei.c:3221 [inline] [] path_openat+0x923/0x3940 fs/namei.c:3357 [] do_filp_open+0x197/0x290 fs/namei.c:3392 [] do_sys_open+0x369/0x660 fs/open.c:1038 [] C_SYSC_openat fs/compat.c:1101 [inline] [] compat_SyS_openat+0x2d/0x40 fs/compat.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] [] __netif_tx_lock include/linux/netdevice.h:3299 [inline] [] sch_direct_xmit+0x23c/0x760 net/sched/sch_generic.c:163 [] __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] [] ip6_finish_output2+0x990/0x1c60 net/ipv6/ip6_output.c:113 [] ip6_finish_output+0x2e6/0x750 net/ipv6/ip6_output.c:131 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip6_output+0x1ab/0x520 net/ipv6/ip6_output.c:145 [] dst_output include/net/dst.h:498 [inline] [] NF_HOOK_THRESH.constprop.24+0x11a/0x320 include/linux/netfilter.h:226 [] NF_HOOK include/linux/netfilter.h:249 [inline] [] ndisc_send_skb+0x816/0xf80 net/ipv6/ndisc.c:471 [] ndisc_send_ns+0x2e6/0x720 net/ipv6/ndisc.c:595 [] ndisc_solicit+0x2a0/0x440 net/ipv6/ndisc.c:686 [] neigh_probe+0xc3/0x100 net/core/neighbour.c:863 [] __neigh_event_send+0x790/0xc40 net/core/neighbour.c:1019 [] neigh_event_send include/net/neighbour.h:431 [inline] [] neigh_resolve_output+0x4aa/0x770 net/core/neighbour.c:1296 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip6_finish_output2+0x990/0x1c60 net/ipv6/ip6_output.c:113 [] ip6_finish_output+0x2e6/0x750 net/ipv6/ip6_output.c:131 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip6_output+0x1ab/0x520 net/ipv6/ip6_output.c:145 [] dst_output include/net/dst.h:498 [inline] [] ip6_local_out+0x95/0x170 net/ipv6/output_core.c:169 [] ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1717 [] ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1737 [] icmpv6_push_pending_frames+0x338/0x530 net/ipv6/icmp.c:276 [] icmp6_send+0x146d/0x1b70 net/ipv6/icmp.c:537 [] 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&q->lock)->rlock#2); lock(_xmit_NETROM); lock(&(&q->lock)->rlock#2); lock(_xmit_NETROM); *** DEADLOCK *** 9 locks held by syz-executor1/12601: #0: (rcu_read_lock){......}, at: [] __skb_unlink include/linux/skbuff.h:1643 [inline] #0: (rcu_read_lock){......}, at: [] __skb_dequeue include/linux/skbuff.h:1659 [inline] #0: (rcu_read_lock){......}, at: [] process_backlog+0x1af/0x690 net/core/dev.c:4644 #1: (rcu_read_lock){......}, at: [] dst_input include/net/dst.h:504 [inline] #1: (rcu_read_lock){......}, at: [] ip6_input_finish+0x0/0x1540 net/ipv6/ip6_input.c:62 #2: (&(&q->lock)->rlock#2){+.-...}, at: [] spin_lock include/linux/spinlock.h:302 [inline] #2: (&(&q->lock)->rlock#2){+.-...}, at: [] ipv6_frag_rcv+0x5e7/0x5020 net/ipv6/reassembly.c:560 #3: (slock-AF_INET6){+.-...}, at: [] spin_trylock include/linux/spinlock.h:312 [inline] #3: (slock-AF_INET6){+.-...}, at: [] icmpv6_xmit_lock net/ipv6/icmp.c:120 [inline] #3: (slock-AF_INET6){+.-...}, at: [] icmp6_send+0x92a/0x1b70 net/ipv6/icmp.c:485 #4: (rcu_read_lock){......}, at: [] icmp6_send+0xfd4/0x1b70 net/ipv6/icmp.c:517 #5: (rcu_read_lock_bh){......}, at: [] ip6_finish_output2+0x1d5/0x1c60 net/ipv6/ip6_output.c:71 #6: (rcu_read_lock){......}, at: [] ip6_nd_hdr net/ipv6/ndisc.c:427 [inline] #6: (rcu_read_lock){......}, at: [] ndisc_send_skb+0x654/0xf80 net/ipv6/ndisc.c:465 #7: (rcu_read_lock_bh){......}, at: [] ip6_finish_output2+0x1d5/0x1c60 net/ipv6/ip6_output.c:71 #8: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x1d5/0x1cc0 net/core/dev.c:3139 stack backtrace: CPU: 1 PID: 12601 Comm: syz-executor1 Not tainted 4.4.125-g38f41ec #21 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 0000000000000000 4df271c8b9e7339d ffff8801db3062f8 ffffffff81d067bd ffffffff851c1f60 ffffffff851c1f60 ffffffff851ea250 ffff8800a33eba48 ffff8800a33eb000 ffff8801db306340 ffffffff81234081 ffff8800a33eba48 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] [] __netif_tx_lock include/linux/netdevice.h:3299 [inline] [] sch_direct_xmit+0x23c/0x760 net/sched/sch_generic.c:163 [] __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] [] ip6_finish_output2+0x990/0x1c60 net/ipv6/ip6_output.c:113 [] ip6_finish_output+0x2e6/0x750 net/ipv6/ip6_output.c:131 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip6_output+0x1ab/0x520 net/ipv6/ip6_output.c:145 [] dst_output include/net/dst.h:498 [inline] [] NF_HOOK_THRESH.constprop.24+0x11a/0x320 include/linux/netfilter.h:226 [] NF_HOOK include/linux/netfilter.h:249 [inline] [] ndisc_send_skb+0x816/0xf80 net/ipv6/ndisc.c:471 [] ndisc_send_ns+0x2e6/0x720 net/ipv6/ndisc.c:595 [] ndisc_solicit+0x2a0/0x440 net/ipv6/ndisc.c:686 [] neigh_probe+0xc3/0x100 net/core/neighbour.c:863 [] __neigh_event_send+0x790/0xc40 net/core/neighbour.c:1019 [] neigh_event_send include/net/neighbour.h:431 [inline] [] neigh_resolve_output+0x4aa/0x770 net/core/neighbour.c:1296 [] dst_neigh_output include/net/dst.h:461 [inline] [] ip6_finish_output2+0x990/0x1c60 net/ipv6/ip6_output.c:113 [] ip6_finish_output+0x2e6/0x750 net/ipv6/ip6_output.c:131 [] NF_HOOK_COND include/linux/netfilter.h:240 [inline] [] ip6_output+0x1ab/0x520 net/ipv6/ip6_output.c:145 [] dst_output include/net/dst.h:498 [inline] [] ip6_local_out+0x95/0x170 net/ipv6/output_core.c:169 [] ip6_send_skb+0xa1/0x340 net/ipv6/ip6_output.c:1717 [] ip6_push_pending_frames+0xb3/0xe0 net/ipv6/ip6_output.c:1737 [] icmpv6_push_pending_frames+0x338/0x530 net/ipv6/icmp.c:276 [] icmp6_send+0x146d/0x1b70 net/ipv6/icmp.c:537 [] 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 IPVS: set_ctl: invalid protocol: 4 224.0.0.2:20000 fo IPVS: set_ctl: invalid protocol: 4 224.0.0.2:20000 fo