[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 20.613486] random: sshd: uninitialized urandom read (32 bytes read, 33 bits of entropy available) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.418371] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 23.826058] random: sshd: uninitialized urandom read (32 bytes read, 37 bits of entropy available) [ 24.913503] random: sshd: uninitialized urandom read (32 bytes read, 124 bits of entropy available) [ 25.071863] random: sshd: uninitialized urandom read (32 bytes read, 127 bits of entropy available) [ 30.306818] random: nonblocking pool is initialized Warning: Permanently added '10.128.0.11' (ECDSA) to the list of known hosts. 2018/04/30 15:57:37 parsed 1 programs 2018/04/30 15:57:37 executed programs: 0 [ 31.088622] IPVS: Creating netns size=2552 id=1 [ 31.147060] IPVS: Creating netns size=2552 id=2 [ 31.211772] IPVS: Creating netns size=2552 id=3 [ 31.307191] IPVS: Creating netns size=2552 id=4 [ 31.416178] IPVS: Creating netns size=2552 id=5 [ 31.592907] IPVS: Creating netns size=2552 id=6 [ 31.645383] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 31.708405] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 31.767431] IPVS: Creating netns size=2552 id=7 [ 31.975812] IPVS: Creating netns size=2552 id=8 [ 32.104553] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.139022] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.164756] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.215096] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.384215] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.458339] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.485807] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 32.579427] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.594398] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 32.652655] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 32.670017] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 32.701847] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.747172] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 32.759189] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.833089] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 32.862526] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.164163] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.180443] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.190458] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.232547] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.244909] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.253941] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.264490] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.277652] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.357076] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.452009] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.464954] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.556200] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.564303] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.575759] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.595884] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.642548] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.653506] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.661620] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.717182] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.730114] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 33.750396] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 33.850508] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.862742] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 33.943316] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 33.953339] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.967813] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.029193] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.053083] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.102165] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.157057] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.179304] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.241032] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.258249] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bond: link is not ready [ 34.274342] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.303846] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.319710] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.333118] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bond: link is not ready [ 34.369419] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.387464] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.448981] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.542341] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.579950] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.686959] ip (4598) used greatest stack depth: 23920 bytes left [ 34.731714] IPv6: ADDRCONF(NETDEV_UP): veth0_to_team: link is not ready [ 34.784579] IPv6: ADDRCONF(NETDEV_UP): veth1_to_team: link is not ready [ 34.859017] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.939699] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 36.563920] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 36.820473] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.134424] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.226050] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.359300] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.437461] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.520110] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.563683] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.577458] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 37.756017] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.828901] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.849567] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 37.865044] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.094100] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 38.194991] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 38.440771] [ 38.442436] ====================================================== [ 38.448737] [ INFO: possible circular locking dependency detected ] [ 38.455214] 4.4.130-g12ef385 #27 Not tainted [ 38.459605] ------------------------------------------------------- [ 38.466001] syz-executor0/5698 is trying to acquire lock: [ 38.471523] (&(&q->lock)->rlock){+.-...}, at: [] ip_defrag+0x318/0x3fe0 [ 38.480442] [ 38.480442] but task is already holding lock: [ 38.486395] (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 [ 38.495231] [ 38.495231] which lock already depends on the new lock. [ 38.495231] [ 38.503536] [ 38.503536] the existing dependency chain (in reverse order) is: [ 38.511141] -> #1 (_xmit_NETROM){+.-...}: [ 38.515951] [] lock_acquire+0x15e/0x450 [ 38.522218] [] _raw_spin_lock_irqsave+0x4e/0x70 [ 38.529264] [] depot_save_stack+0x211/0x610 [ 38.535889] [] save_stack+0xa9/0xd0 [ 38.541813] [] kasan_kmalloc+0xc7/0xe0 [ 38.547993] [] kasan_slab_alloc+0x12/0x20 [ 38.554441] [] kmem_cache_alloc+0xbe/0x2a0 [ 38.560982] [] inet_getpeer.part.5+0xeac/0x15a0 [ 38.567954] [] inet_getpeer+0x55b/0x6f0 [ 38.574219] [] icmp6_send+0x17c5/0x1b80 [ 38.580487] [] icmpv6_param_prob+0x29/0x40 [ 38.587038] [] ipv6_frag_rcv+0x3f94/0x4fd0 [ 38.593561] [] ip6_input_finish+0x32e/0x1550 [ 38.600267] [] ip6_input+0xf6/0x200 [ 38.606178] [] ip6_rcv_finish+0x13d/0x640 [ 38.612618] [] ipv6_rcv+0x10cb/0x1cd0 [ 38.618712] [] __netif_receive_skb_core+0x12d6/0x2940 [ 38.626194] [] __netif_receive_skb+0x5b/0x1b0 [ 38.632982] [] process_backlog+0x216/0x6a0 [ 38.639512] [] net_rx_action+0x3a2/0xdb0 [ 38.645867] [] __do_softirq+0x22c/0xa1a [ 38.652134] [] do_softirq_own_stack+0x1c/0x30 [ 38.658916] [] do_softirq.part.16+0x54/0x60 [ 38.665526] [] do_softirq+0x19/0x20 [ 38.671444] [] netif_rx_ni+0xec/0x3a0 [ 38.677534] [] tun_get_user+0xbe7/0x2410 [ 38.683886] [] tun_chr_write_iter+0xd5/0x190 [ 38.690584] [] do_iter_readv_writev+0x13c/0x1e0 [ 38.697547] [] compat_do_readv_writev+0x2e2/0x6e0 [ 38.704684] [] compat_writev+0xe1/0x150 [ 38.710951] [] compat_SyS_writev+0xd8/0x1c0 [ 38.717562] [] do_fast_syscall_32+0x326/0x8b0 [ 38.724368] [] sysenter_flags_fixed+0xd/0x17 [ 38.731071] -> #0 (&(&q->lock)->rlock){+.-...}: [ 38.736413] [] __lock_acquire+0x3902/0x5270 [ 38.743030] [] lock_acquire+0x15e/0x450 [ 38.749294] [] _raw_spin_lock+0x36/0x50 [ 38.755558] [] ip_defrag+0x318/0x3fe0 [ 38.761651] [] ip_check_defrag+0x3c8/0x7e0 [ 38.768176] [] packet_rcv_fanout+0x52a/0x5e0 [ 38.774877] [] dev_hard_start_xmit+0x644/0x11c0 [ 38.781836] [] sch_direct_xmit+0x2c1/0x6e0 [ 38.788360] [] __dev_queue_xmit+0xef3/0x1c80 [ 38.795057] [] dev_queue_xmit+0x17/0x20 [ 38.801322] [] neigh_resolve_output+0x637/0x790 [ 38.808280] [] ip_finish_output2+0x6ab/0x1110 [ 38.815065] [] ip_do_fragment+0x198b/0x2150 [ 38.821672] [] ip_fragment.constprop.50+0x143/0x200 [ 38.828985] [] ip_finish_output+0x6c4/0xbc0 [ 38.835602] [] ip_mc_output+0x233/0x980 [ 38.841866] [] ip_local_out+0x9b/0x180 [ 38.848040] [] ip_send_skb+0x3c/0xc0 [ 38.854042] [] udp_send_skb+0x5c3/0xc60 [ 38.860310] [] udp_sendmsg+0x16ce/0x1bb0 [ 38.866664] [] inet_sendmsg+0x203/0x4d0 [ 38.872925] [] sock_sendmsg+0xcc/0x110 [ 38.879103] [] SYSC_sendto+0x21c/0x370 [ 38.885283] [] SyS_sendto+0x40/0x50 [ 38.891197] [] do_fast_syscall_32+0x326/0x8b0 [ 38.897982] [] sysenter_flags_fixed+0xd/0x17 [ 38.904681] [ 38.904681] other info that might help us debug this: [ 38.904681] [ 38.912808] Possible unsafe locking scenario: [ 38.912808] [ 38.918851] CPU0 CPU1 [ 38.923500] ---- ---- [ 38.928147] lock(_xmit_NETROM); [ 38.931836] lock(&(&q->lock)->rlock); [ 38.938558] lock(_xmit_NETROM); [ 38.944765] lock(&(&q->lock)->rlock); [ 38.948983] [ 38.948983] *** DEADLOCK *** [ 38.948983] [ 38.955033] 4 locks held by syz-executor0/5698: [ 38.959684] #0: (rcu_read_lock_bh){......}, at: [] ip_finish_output2+0x212/0x1110 [ 38.969685] #1: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x1d7/0x1c80 [ 38.979600] #2: (_xmit_NETROM){+.-...}, at: [] sch_direct_xmit+0x23c/0x6e0 [ 38.988994] #3: (rcu_read_lock){......}, at: [] dev_hard_start_xmit+0xa8/0x11c0 [ 38.998816] [ 38.998816] stack backtrace: [ 39.003302] CPU: 1 PID: 5698 Comm: syz-executor0 Not tainted 4.4.130-g12ef385 #27 [ 39.010908] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 39.020246] 0000000000000000 87a8540291b62412 ffff8801d98cecc8 ffffffff81e0dc6d [ 39.028282] ffffffff853ed730 ffffffff853eb8d0 ffffffff853ed730 ffff8801d8ce2150 [ 39.036316] ffff8801d8ce1800 ffff8801d98ced10 ffffffff8140e3eb 0000000000000003 [ 39.044349] Call Trace: [ 39.046929] [] dump_stack+0xc1/0x124 [ 39.052370] [] print_circular_bug.cold.50+0x1bd/0x27d [ 39.059203] [] __lock_acquire+0x3902/0x5270 [ 39.065166] [] ? trace_hardirqs_on_thunk+0x17/0x19 [ 39.071746] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.078755] [] lock_acquire+0x15e/0x450 [ 39.084374] [] ? ip_defrag+0x318/0x3fe0 [ 39.089992] [] ? inet_frag_find+0x22e/0x9c0 [ 39.096821] [] _raw_spin_lock+0x36/0x50 [ 39.102438] [] ? ip_defrag+0x318/0x3fe0 [ 39.108050] [] ip_defrag+0x318/0x3fe0 [ 39.113496] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.120498] [] ? memcpy+0x45/0x50 [ 39.125592] [] ? ip_expire+0x770/0x770 [ 39.131120] [] ip_check_defrag+0x3c8/0x7e0 [ 39.137093] [] ? ip_defrag+0x3fe0/0x3fe0 [ 39.142796] [] packet_rcv_fanout+0x52a/0x5e0 [ 39.148850] [] ? packet_bind+0x190/0x190 [ 39.154557] [] dev_hard_start_xmit+0x644/0x11c0 [ 39.160873] [] ? dev_hard_start_xmit+0xa8/0x11c0 [ 39.161043] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 39.173740] [] sch_direct_xmit+0x2c1/0x6e0 [ 39.179618] [] ? dev_watchdog+0x7f0/0x7f0 [ 39.185411] [] __dev_queue_xmit+0xef3/0x1c80 [ 39.191464] [] ? __dev_queue_xmit+0x1d7/0x1c80 [ 39.197694] [] ? debug_check_no_locks_freed+0x210/0x210 [ 39.204789] [] ? netdev_pick_tx+0x2c0/0x2c0 [ 39.210750] [] ? memcpy+0x45/0x50 [ 39.215846] [] dev_queue_xmit+0x17/0x20 [ 39.221459] [] neigh_resolve_output+0x637/0x790 [ 39.227771] [] ? ip_finish_output2+0x6ab/0x1110 [ 39.234085] [] ip_finish_output2+0x6ab/0x1110 [ 39.240224] [] ? ip_finish_output2+0x212/0x1110 [ 39.246601] [] ? nf_ct_deliver_cached_events+0x335/0x560 [ 39.253702] [] ? nf_ct_deliver_cached_events+0x83/0x560 [ 39.260712] [] ? ip_copy_metadata+0x700/0x700 [ 39.266856] [] ? ip_options_fragment+0x1ac/0x280 [ 39.273258] [] ip_do_fragment+0x198b/0x2150 [ 39.279229] [] ? ip_copy_metadata+0x700/0x700 [ 39.285370] [] ip_fragment.constprop.50+0x143/0x200 [ 39.292035] [] ip_finish_output+0x6c4/0xbc0 [ 39.298001] [] ip_mc_output+0x233/0x980 [ 39.303619] [] ? ip_queue_xmit+0x1ab0/0x1ab0 [ 39.309679] [] ? ip_make_skb+0x116/0x210 [ 39.315386] [] ? ip_fragment.constprop.50+0x200/0x200 [ 39.322223] [] ? ip_flush_pending_frames+0x30/0x30 [ 39.328804] [] ip_local_out+0x9b/0x180 [ 39.334385] [] ip_send_skb+0x3c/0xc0 [ 39.339747] [] udp_send_skb+0x5c3/0xc60 [ 39.345371] [] udp_sendmsg+0x16ce/0x1bb0 [ 39.351082] [] ? ip_reply_glue_bits+0xc0/0xc0 [ 39.357225] [] ? udp4_lib_lookup+0x60/0x60 [ 39.363130] [] ? ip4_datagram_connect+0x50/0x50 [ 39.369447] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 39.375765] [] ? __local_bh_enable_ip+0x6a/0xd0 [ 39.382083] [] ? _raw_spin_unlock_bh+0x30/0x40 [ 39.388308] [] ? release_sock+0x3b6/0x500 [ 39.394101] [] ? udp_v4_get_port+0x139/0x180 [ 39.400153] [] inet_sendmsg+0x203/0x4d0 [ 39.405769] [] ? inet_sendmsg+0x73/0x4d0 [ 39.411473] [] ? inet_recvmsg+0x4c0/0x4c0 [ 39.418046] [] sock_sendmsg+0xcc/0x110 [ 39.423575] [] SYSC_sendto+0x21c/0x370 [ 39.429105] [] ? SYSC_connect+0x300/0x300 [ 39.434898] [] ? sock_has_perm+0x29f/0x400 [ 39.440786] [] ? selinux_file_send_sigiotask+0x310/0x310 [ 39.447883] [] ? compat_sock_setsockopt.constprop.6+0xad/0x4c0 [ 39.455505] [] ? compat_SyS_futex+0x1e1/0x2f0 [ 39.461652] [] ? compat_SyS_get_robust_list+0x310/0x310 [ 39.468660] [] ? compat_SyS_setsockopt+0x18d/0x2a0 [ 39.475234] [] ? SyS_socket+0x121/0x1b0 [ 39.480851] [] ? scm_detach_fds_compat+0x3b0/0x3b0 [ 39.487427] [] SyS_sendto+0x40/0x50 [ 39.492698] [] ? SyS_getpeername+0x30/0x30 [ 39.498574] [] do_fast_syscall_32+0x326/0x8b0 [ 39.504980] [] sysenter_flags_fixed+0xd/0x17 2018/04/30 15:57:45 executed programs: 8 2018/04/30 15:57:50 executed programs: 283