[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 24.454836] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 30.326227] random: sshd: uninitialized urandom read (32 bytes read) [ 30.821768] random: sshd: uninitialized urandom read (32 bytes read) [ 31.393929] random: sshd: uninitialized urandom read (32 bytes read) [ 103.382096] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.45' (ECDSA) to the list of known hosts. [ 108.987847] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/29 21:24:49 parsed 1 programs [ 110.271859] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/29 21:24:51 executed programs: 0 [ 111.667131] IPVS: ftp: loaded support on port[0] = 21 [ 111.886920] bridge0: port 1(bridge_slave_0) entered blocking state [ 111.893488] bridge0: port 1(bridge_slave_0) entered disabled state [ 111.901815] device bridge_slave_0 entered promiscuous mode [ 111.919534] bridge0: port 2(bridge_slave_1) entered blocking state [ 111.925909] bridge0: port 2(bridge_slave_1) entered disabled state [ 111.933248] device bridge_slave_1 entered promiscuous mode [ 111.951015] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 111.967824] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 112.012885] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 112.032267] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 112.099756] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 112.107059] team0: Port device team_slave_0 added [ 112.123867] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 112.131062] team0: Port device team_slave_1 added [ 112.147911] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 112.167065] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 112.185086] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 112.204098] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 112.341665] bridge0: port 2(bridge_slave_1) entered blocking state [ 112.348144] bridge0: port 2(bridge_slave_1) entered forwarding state [ 112.355171] bridge0: port 1(bridge_slave_0) entered blocking state [ 112.361561] bridge0: port 1(bridge_slave_0) entered forwarding state [ 112.826787] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 112.833056] 8021q: adding VLAN 0 to HW filter on device bond0 [ 112.857691] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 112.887020] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 112.931596] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 112.937753] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 112.945072] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 112.982494] 8021q: adding VLAN 0 to HW filter on device team0 [ 113.254335] [ 113.256103] ====================================================== [ 113.262401] WARNING: possible circular locking dependency detected [ 113.268700] 4.19.0-rc1-next-20180829+ #50 Not tainted [ 113.273867] ------------------------------------------------------ [ 113.280167] syz-executor0/4726 is trying to acquire lock: [ 113.285684] 000000002e884443 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 113.294951] [ 113.294951] but task is already holding lock: [ 113.300902] 00000000c58b6e3d (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 113.308899] [ 113.308899] which lock already depends on the new lock. [ 113.308899] [ 113.317251] [ 113.317251] the existing dependency chain (in reverse order) is: [ 113.324859] [ 113.324859] -> #2 (rtnl_mutex){+.+.}: [ 113.330229] __mutex_lock+0x171/0x1700 [ 113.334620] mutex_lock_nested+0x16/0x20 [ 113.339298] rtnl_lock+0x17/0x20 [ 113.343171] bond_netdev_notify_work+0x44/0xd0 [ 113.348345] process_one_work+0xc73/0x1aa0 [ 113.353087] worker_thread+0x189/0x13c0 [ 113.357562] kthread+0x35a/0x420 [ 113.361429] ret_from_fork+0x3a/0x50 [ 113.365637] [ 113.365637] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 113.373359] process_one_work+0xc0b/0x1aa0 [ 113.378140] worker_thread+0x189/0x13c0 [ 113.382620] kthread+0x35a/0x420 [ 113.386530] ret_from_fork+0x3a/0x50 [ 113.390845] [ 113.390845] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 113.397827] lock_acquire+0x1e4/0x4f0 [ 113.402151] flush_workqueue+0x30a/0x1e10 [ 113.406822] drain_workqueue+0x2a9/0x640 [ 113.411390] destroy_workqueue+0xc6/0x9d0 [ 113.416039] __alloc_workqueue_key+0xef9/0x1190 [ 113.421250] bond_init+0x269/0x940 [ 113.425392] register_netdevice+0x337/0x1100 [ 113.430348] bond_newlink+0x49/0xa0 [ 113.434483] rtnl_newlink+0xef4/0x1d50 [ 113.438993] rtnetlink_rcv_msg+0x46e/0xc30 [ 113.443731] netlink_rcv_skb+0x172/0x440 [ 113.448385] rtnetlink_rcv+0x1c/0x20 [ 113.452642] netlink_unicast+0x5a0/0x760 [ 113.457210] netlink_sendmsg+0xa18/0xfc0 [ 113.461793] sock_sendmsg+0xd5/0x120 [ 113.466008] ___sys_sendmsg+0x7fd/0x930 [ 113.470495] __sys_sendmsg+0x11d/0x290 [ 113.474916] __x64_sys_sendmsg+0x78/0xb0 [ 113.479486] do_syscall_64+0x1b9/0x820 [ 113.483958] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 113.489677] [ 113.489677] other info that might help us debug this: [ 113.489677] [ 113.497798] Chain exists of: [ 113.497798] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 113.497798] [ 113.511504] Possible unsafe locking scenario: [ 113.511504] [ 113.517543] CPU0 CPU1 [ 113.522187] ---- ---- [ 113.526883] lock(rtnl_mutex); [ 113.530147] lock((work_completion)(&(&nnw->work)->work)); [ 113.538352] lock(rtnl_mutex); [ 113.544295] lock((wq_completion)bond_dev->name); [ 113.549207] [ 113.549207] *** DEADLOCK *** [ 113.549207] [ 113.555249] 1 lock held by syz-executor0/4726: [ 113.559995] #0: 00000000c58b6e3d (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 113.568229] [ 113.568229] stack backtrace: [ 113.572709] CPU: 1 PID: 4726 Comm: syz-executor0 Not tainted 4.19.0-rc1-next-20180829+ #50 [ 113.581098] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 113.590442] Call Trace: [ 113.593014] dump_stack+0x1c9/0x2b4 [ 113.596620] ? dump_stack_print_info.cold.2+0x52/0x52 [ 113.601849] ? vprintk_func+0x81/0x117 [ 113.605725] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 113.611413] ? save_trace+0xe0/0x290 [ 113.615108] __lock_acquire+0x3449/0x5020 [ 113.619235] ? mark_held_locks+0x160/0x160 [ 113.623472] ? mark_held_locks+0x160/0x160 [ 113.627688] ? __lock_is_held+0xb5/0x140 [ 113.631726] ? __account_cfs_rq_runtime+0x770/0x770 [ 113.636721] ? set_next_entity+0x2f0/0xa80 [ 113.640977] ? lock_downgrade+0x8f0/0x8f0 [ 113.645150] lock_acquire+0x1e4/0x4f0 [ 113.649088] ? flush_workqueue+0x2db/0x1e10 [ 113.653535] ? lock_release+0x9f0/0x9f0 [ 113.657487] ? lockdep_init_map+0x9/0x10 [ 113.661588] ? __init_waitqueue_head+0x9e/0x150 [ 113.666244] ? init_wait_entry+0x1c0/0x1c0 [ 113.670539] flush_workqueue+0x30a/0x1e10 [ 113.674738] ? flush_workqueue+0x2db/0x1e10 [ 113.679055] ? lock_acquire+0x1e4/0x4f0 [ 113.683013] ? drain_workqueue+0xa9/0x640 [ 113.687150] ? lock_release+0x9f0/0x9f0 [ 113.691170] ? check_same_owner+0x340/0x340 [ 113.695476] ? __queue_delayed_work+0x390/0x390 [ 113.700132] ? graph_lock+0x170/0x170 [ 113.703931] ? kasan_check_write+0x14/0x20 [ 113.708149] ? __mutex_lock+0x6d0/0x1700 [ 113.712189] ? drain_workqueue+0xa9/0x640 [ 113.716388] ? finish_task_switch+0x2ca/0x870 [ 113.720894] ? find_held_lock+0x36/0x1c0 [ 113.724936] ? lock_downgrade+0x8f0/0x8f0 [ 113.729074] ? __schedule+0x884/0x1df0 [ 113.733022] ? graph_lock+0x170/0x170 [ 113.736814] ? find_held_lock+0x36/0x1c0 [ 113.740866] ? kasan_check_write+0x14/0x20 [ 113.745084] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 113.749992] ? wait_for_completion+0x8d0/0x8d0 [ 113.754559] ? do_raw_spin_unlock+0xa7/0x2f0 [ 113.758948] ? trace_hardirqs_on+0x2c0/0x2c0 [ 113.763344] drain_workqueue+0x2a9/0x640 [ 113.767389] ? drain_workqueue+0x2a9/0x640 [ 113.771608] ? flush_workqueue+0x1e10/0x1e10 [ 113.775999] ? save_stack+0xa9/0xd0 [ 113.779650] ? save_stack+0x43/0xd0 [ 113.783263] ? __kasan_slab_free+0x11a/0x170 [ 113.789005] ? kasan_slab_free+0xe/0x10 [ 113.792962] ? print_usage_bug+0xc0/0xc0 [ 113.797003] ? bond_init+0x269/0x940 [ 113.800703] ? register_netdevice+0x337/0x1100 [ 113.805271] ? bond_newlink+0x49/0xa0 [ 113.809057] ? rtnl_newlink+0xef4/0x1d50 [ 113.813104] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 113.817493] ? netlink_rcv_skb+0x172/0x440 [ 113.821777] ? rtnetlink_rcv+0x1c/0x20 [ 113.825649] ? netlink_unicast+0x5a0/0x760 [ 113.829907] ? netlink_sendmsg+0xa18/0xfc0 [ 113.834139] ? sock_sendmsg+0xd5/0x120 [ 113.838080] destroy_workqueue+0xc6/0x9d0 [ 113.842218] ? kasan_check_write+0x14/0x20 [ 113.846435] ? wq_watchdog_timer_fn+0x830/0x830 [ 113.851093] ? mark_held_locks+0xc9/0x160 [ 113.855222] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 113.860315] ? kfree+0x111/0x210 [ 113.863667] ? kfree+0x111/0x210 [ 113.867023] ? lockdep_hardirqs_on+0x421/0x5c0 [ 113.871586] ? trace_hardirqs_on+0xbd/0x2c0 [ 113.875926] ? init_rescuer.part.26+0x155/0x190 [ 113.880590] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 113.885676] ? __kasan_slab_free+0x131/0x170 [ 113.890069] ? init_rescuer.part.26+0x155/0x190 [ 113.894725] __alloc_workqueue_key+0xef9/0x1190 [ 113.899386] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 113.904908] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 113.910078] ? put_dec+0xf0/0xf0 [ 113.913473] ? format_decode+0x1b1/0xaf0 [ 113.917548] ? set_precision+0xe0/0xe0 [ 113.921414] ? simple_strtoll+0xa0/0xa0 [ 113.925936] ? graph_lock+0x170/0x170 [ 113.929726] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 113.935250] ? vsnprintf+0x20d/0x1b60 [ 113.939038] ? find_held_lock+0x36/0x1c0 [ 113.943169] ? lock_downgrade+0x8f0/0x8f0 [ 113.947415] ? kasan_check_read+0x11/0x20 [ 113.951552] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 113.956218] bond_init+0x269/0x940 [ 113.959806] ? __dev_get_by_name+0x170/0x170 [ 113.964244] ? bond_arp_rcv+0x11c0/0x11c0 [ 113.968384] ? check_same_owner+0x340/0x340 [ 113.972688] ? rcu_note_context_switch+0x680/0x680 [ 113.977649] ? bond_arp_rcv+0x11c0/0x11c0 [ 113.981788] register_netdevice+0x337/0x1100 [ 113.986179] ? netdev_change_features+0x110/0x110 [ 113.991009] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 113.996526] ? ns_capable_common+0x13f/0x170 [ 114.000920] bond_newlink+0x49/0xa0 [ 114.004528] ? bond_changelink+0x2360/0x2360 [ 114.008932] rtnl_newlink+0xef4/0x1d50 [ 114.012808] ? rtnl_link_unregister+0x390/0x390 [ 114.017463] ? print_usage_bug+0xc0/0xc0 [ 114.021512] ? __lock_acquire+0x7fc/0x5020 [ 114.025726] ? print_usage_bug+0xc0/0xc0 [ 114.029770] ? graph_lock+0x170/0x170 [ 114.033551] ? print_usage_bug+0xc0/0xc0 [ 114.037593] ? mark_held_locks+0x160/0x160 [ 114.041811] ? __lock_acquire+0x7fc/0x5020 [ 114.046026] ? lock_acquire+0x1e4/0x4f0 [ 114.049979] ? rtnetlink_rcv_msg+0x412/0xc30 [ 114.054475] ? lock_release+0x9f0/0x9f0 [ 114.058521] ? check_same_owner+0x340/0x340 [ 114.062831] ? mutex_trylock+0x2b0/0x2b0 [ 114.066875] ? __lock_acquire+0x7fc/0x5020 [ 114.071104] ? graph_lock+0x170/0x170 [ 114.074898] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 114.080425] ? rtnl_get_link+0x170/0x370 [ 114.084470] ? rtnl_dump_all+0x600/0x600 [ 114.088522] ? rcu_is_watching+0x8c/0x150 [ 114.092701] ? rtnl_link_unregister+0x390/0x390 [ 114.097360] rtnetlink_rcv_msg+0x46e/0xc30 [ 114.101575] ? rtnetlink_put_metrics+0x690/0x690 [ 114.106318] netlink_rcv_skb+0x172/0x440 [ 114.110367] ? rtnetlink_put_metrics+0x690/0x690 [ 114.115112] ? netlink_ack+0xbe0/0xbe0 [ 114.118999] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 114.123655] rtnetlink_rcv+0x1c/0x20 [ 114.127478] netlink_unicast+0x5a0/0x760 [ 114.131635] ? netlink_attachskb+0x9a0/0x9a0 [ 114.136030] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 114.141557] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 114.146703] netlink_sendmsg+0xa18/0xfc0 [ 114.150752] ? netlink_unicast+0x760/0x760 [ 114.154973] ? move_addr_to_kernel.part.18+0x100/0x100 [ 114.160239] ? security_socket_sendmsg+0x94/0xc0 [ 114.164984] ? netlink_unicast+0x760/0x760 [ 114.169205] sock_sendmsg+0xd5/0x120 [ 114.172954] ___sys_sendmsg+0x7fd/0x930 [ 114.176923] ? copy_msghdr_from_user+0x580/0x580 [ 114.181664] ? lock_downgrade+0x8f0/0x8f0 [ 114.185801] ? __fget_light+0x2f7/0x440 [ 114.189760] ? fget_raw+0x20/0x20 [ 114.193193] ? __fd_install+0x2db/0x880 [ 114.197153] ? get_unused_fd_flags+0x1a0/0x1a0 [ 114.201727] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 114.207251] ? sockfd_lookup_light+0xc5/0x160 [ 114.211725] __sys_sendmsg+0x11d/0x290 [ 114.215607] ? __ia32_sys_shutdown+0x80/0x80 [ 114.219999] ? __x64_sys_futex+0x47f/0x6a0 [ 114.224223] ? do_syscall_64+0x9a/0x820 [ 114.228188] ? do_syscall_64+0x9a/0x820 [ 114.232152] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 114.237258] ? trace_hardirqs_off+0xb8/0x2b0 [ 114.241672] __x64_sys_sendmsg+0x78/0xb0 [ 114.245722] do_syscall_64+0x1b9/0x820 [ 114.249594] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 114.254941] ? syscall_return_slowpath+0x5e0/0x5e0 [ 114.259857] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 114.264877] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 114.269878] ? recalc_sigpending_tsk+0x180/0x180 [ 114.274620] ? kasan_check_write+0x14/0x20 [ 114.278862] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 114.283693] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 114.288873] RIP: 0033:0x457089 [ 114.292050] Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b4 fb ff c3 66 2e