[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.655340] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.190134] random: sshd: uninitialized urandom read (32 bytes read) [ 25.580928] random: sshd: uninitialized urandom read (32 bytes read) [ 26.131451] random: sshd: uninitialized urandom read (32 bytes read) [ 26.316106] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.206' (ECDSA) to the list of known hosts. [ 32.075007] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/04 14:41:10 parsed 1 programs [ 33.457102] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/04 14:41:12 executed programs: 0 [ 34.597628] IPVS: ftp: loaded support on port[0] = 21 [ 34.834116] bridge0: port 1(bridge_slave_0) entered blocking state [ 34.840688] bridge0: port 1(bridge_slave_0) entered disabled state [ 34.848507] device bridge_slave_0 entered promiscuous mode [ 34.867423] bridge0: port 2(bridge_slave_1) entered blocking state [ 34.873840] bridge0: port 2(bridge_slave_1) entered disabled state [ 34.881281] device bridge_slave_1 entered promiscuous mode [ 34.898276] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.915726] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 34.963970] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 34.984378] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 35.057244] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 35.064581] team0: Port device team_slave_0 added [ 35.080853] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 35.088169] team0: Port device team_slave_1 added [ 35.105388] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 35.124953] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 35.144408] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 35.163299] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 35.305967] bridge0: port 2(bridge_slave_1) entered blocking state [ 35.312444] bridge0: port 2(bridge_slave_1) entered forwarding state [ 35.319526] bridge0: port 1(bridge_slave_0) entered blocking state [ 35.325929] bridge0: port 1(bridge_slave_0) entered forwarding state [ 35.829949] 8021q: adding VLAN 0 to HW filter on device bond0 [ 35.880745] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 35.931465] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 35.937885] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 35.945330] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 35.996395] 8021q: adding VLAN 0 to HW filter on device team0 [ 36.322856] [ 36.324673] ====================================================== [ 36.330984] WARNING: possible circular locking dependency detected [ 36.337306] 4.19.0-rc2+ #220 Not tainted [ 36.341438] ------------------------------------------------------ [ 36.347762] syz-executor0/4918 is trying to acquire lock: [ 36.353304] 00000000d7d800b6 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 36.362591] [ 36.362591] but task is already holding lock: [ 36.368568] 00000000f1b59770 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 36.376287] [ 36.376287] which lock already depends on the new lock. [ 36.376287] [ 36.384933] [ 36.384933] the existing dependency chain (in reverse order) is: [ 36.392551] [ 36.392551] -> #2 (rtnl_mutex){+.+.}: [ 36.397849] __mutex_lock+0x171/0x1700 [ 36.402272] mutex_lock_nested+0x16/0x20 [ 36.406858] rtnl_lock+0x17/0x20 [ 36.410754] bond_netdev_notify_work+0x44/0xd0 [ 36.416020] process_one_work+0xc73/0x1aa0 [ 36.420778] worker_thread+0x189/0x13c0 [ 36.425286] kthread+0x35a/0x420 [ 36.429172] ret_from_fork+0x3a/0x50 [ 36.433478] [ 36.433478] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 36.441305] process_one_work+0xc0b/0x1aa0 [ 36.446060] worker_thread+0x189/0x13c0 [ 36.450618] kthread+0x35a/0x420 [ 36.454505] ret_from_fork+0x3a/0x50 [ 36.458814] [ 36.458814] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 36.465779] lock_acquire+0x1e4/0x4f0 [ 36.470263] flush_workqueue+0x30a/0x1e10 [ 36.474930] drain_workqueue+0x2a9/0x640 [ 36.479575] destroy_workqueue+0xc6/0x9d0 [ 36.484278] __alloc_workqueue_key+0xef9/0x1190 [ 36.489479] bond_init+0x269/0x940 [ 36.493540] register_netdevice+0x337/0x1100 [ 36.498467] bond_newlink+0x49/0xa0 [ 36.502623] rtnl_newlink+0xef4/0x1d50 [ 36.507031] rtnetlink_rcv_msg+0x46e/0xc30 [ 36.511794] netlink_rcv_skb+0x172/0x440 [ 36.516389] rtnetlink_rcv+0x1c/0x20 [ 36.520624] netlink_unicast+0x5a0/0x760 [ 36.525233] netlink_sendmsg+0xa18/0xfc0 [ 36.529842] sock_sendmsg+0xd5/0x120 [ 36.534090] ___sys_sendmsg+0x7fd/0x930 [ 36.538587] __sys_sendmsg+0x11d/0x290 [ 36.542998] __x64_sys_sendmsg+0x78/0xb0 [ 36.547679] do_syscall_64+0x1b9/0x820 [ 36.552086] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 36.557792] [ 36.557792] other info that might help us debug this: [ 36.557792] [ 36.565943] Chain exists of: [ 36.565943] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 36.565943] [ 36.579896] Possible unsafe locking scenario: [ 36.579896] [ 36.585955] CPU0 CPU1 [ 36.590627] ---- ---- [ 36.595288] lock(rtnl_mutex); [ 36.598568] lock((work_completion)(&(&nnw->work)->work)); [ 36.606814] lock(rtnl_mutex); [ 36.612687] lock((wq_completion)bond_dev->name); [ 36.617617] [ 36.617617] *** DEADLOCK *** [ 36.617617] [ 36.623682] 1 lock held by syz-executor0/4918: [ 36.628378] #0: 00000000f1b59770 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 36.636529] [ 36.636529] stack backtrace: [ 36.641026] CPU: 0 PID: 4918 Comm: syz-executor0 Not tainted 4.19.0-rc2+ #220 [ 36.648440] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.657900] Call Trace: [ 36.660490] dump_stack+0x1c9/0x2b4 [ 36.664119] ? dump_stack_print_info.cold.2+0x52/0x52 [ 36.669311] ? vprintk_func+0x81/0x117 [ 36.673230] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 36.679006] ? save_trace+0xe0/0x290 [ 36.682721] __lock_acquire+0x3449/0x5020 [ 36.686877] ? mark_held_locks+0x160/0x160 [ 36.691131] ? print_usage_bug+0xc0/0xc0 [ 36.695235] ? mark_held_locks+0x160/0x160 [ 36.699474] ? __lock_is_held+0xb5/0x140 [ 36.703687] ? mark_held_locks+0xc9/0x160 [ 36.707863] ? lockdep_hardirqs_on+0x421/0x5c0 [ 36.712457] lock_acquire+0x1e4/0x4f0 [ 36.716278] ? flush_workqueue+0x2db/0x1e10 [ 36.720614] ? lock_release+0x9f0/0x9f0 [ 36.724584] ? lockdep_init_map+0x9/0x10 [ 36.728642] ? __init_waitqueue_head+0x9e/0x150 [ 36.733309] ? init_wait_entry+0x1c0/0x1c0 [ 36.737545] ? retint_kernel+0x10/0x10 [ 36.741443] flush_workqueue+0x30a/0x1e10 [ 36.745606] ? flush_workqueue+0x2db/0x1e10 [ 36.749928] ? lock_release+0x9f0/0x9f0 [ 36.753903] ? check_same_owner+0x340/0x340 [ 36.758256] ? __queue_delayed_work+0x390/0x390 [ 36.763024] ? graph_lock+0x170/0x170 [ 36.766836] ? kasan_check_write+0x14/0x20 [ 36.771091] ? __mutex_lock+0x6d0/0x1700 [ 36.775166] ? drain_workqueue+0xa9/0x640 [ 36.779315] ? finish_task_switch+0x2ca/0x870 [ 36.783821] ? find_held_lock+0x36/0x1c0 [ 36.787906] ? lock_downgrade+0x8f0/0x8f0 [ 36.792062] ? __schedule+0x884/0x1df0 [ 36.795948] ? graph_lock+0x170/0x170 [ 36.799755] ? find_held_lock+0x36/0x1c0 [ 36.803842] ? kasan_check_write+0x14/0x20 [ 36.808262] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 36.813192] ? wait_for_completion+0x8d0/0x8d0 [ 36.817827] ? do_raw_spin_unlock+0xa7/0x2f0 [ 36.822266] ? trace_hardirqs_on+0x2c0/0x2c0 [ 36.826676] drain_workqueue+0x2a9/0x640 [ 36.830736] ? drain_workqueue+0x2a9/0x640 [ 36.834980] ? flush_workqueue+0x1e10/0x1e10 [ 36.839393] ? save_stack+0xa9/0xd0 [ 36.843015] ? save_stack+0x43/0xd0 [ 36.846633] ? __kasan_slab_free+0x11a/0x170 [ 36.851032] ? kasan_slab_free+0xe/0x10 [ 36.854995] ? print_usage_bug+0xc0/0xc0 [ 36.859050] ? bond_init+0x269/0x940 [ 36.862756] ? register_netdevice+0x337/0x1100 [ 36.867333] ? bond_newlink+0x49/0xa0 [ 36.871117] ? rtnl_newlink+0xef4/0x1d50 [ 36.875160] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 36.879551] ? netlink_rcv_skb+0x172/0x440 [ 36.883769] ? rtnetlink_rcv+0x1c/0x20 [ 36.887648] ? netlink_unicast+0x5a0/0x760 [ 36.891863] ? netlink_sendmsg+0xa18/0xfc0 [ 36.896095] ? sock_sendmsg+0xd5/0x120 [ 36.899967] destroy_workqueue+0xc6/0x9d0 [ 36.904100] ? kasan_check_write+0x14/0x20 [ 36.908345] ? wq_watchdog_timer_fn+0x830/0x830 [ 36.912999] ? mark_held_locks+0xc9/0x160 [ 36.917133] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 36.922229] ? kfree+0x111/0x210 [ 36.925579] ? kfree+0x111/0x210 [ 36.928930] ? lockdep_hardirqs_on+0x421/0x5c0 [ 36.933496] ? trace_hardirqs_on+0xbd/0x2c0 [ 36.937809] ? init_rescuer.part.26+0x155/0x190 [ 36.942470] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.947556] ? __kasan_slab_free+0x131/0x170 [ 36.951948] ? init_rescuer.part.26+0x155/0x190 [ 36.956603] __alloc_workqueue_key+0xef9/0x1190 [ 36.961275] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.966813] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 36.971831] ? put_dec+0xf0/0xf0 [ 36.975187] ? format_decode+0x1b1/0xaf0 [ 36.979252] ? set_precision+0xe0/0xe0 [ 36.983147] ? simple_strtoll+0xa0/0xa0 [ 36.987120] ? graph_lock+0x170/0x170 [ 36.990921] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.996471] ? vsnprintf+0x20d/0x1b60 [ 37.000263] ? find_held_lock+0x36/0x1c0 [ 37.004315] ? lock_downgrade+0x8f0/0x8f0 [ 37.008451] ? kasan_check_read+0x11/0x20 [ 37.012588] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 37.017256] bond_init+0x269/0x940 [ 37.020796] ? __dev_get_by_name+0x170/0x170 [ 37.025229] ? bond_arp_rcv+0x11c0/0x11c0 [ 37.029444] ? check_same_owner+0x340/0x340 [ 37.033761] ? rcu_note_context_switch+0x680/0x680 [ 37.038698] ? bond_arp_rcv+0x11c0/0x11c0 [ 37.042848] register_netdevice+0x337/0x1100 [ 37.047255] ? netdev_change_features+0x110/0x110 [ 37.052104] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 37.057646] ? ns_capable_common+0x13f/0x170 [ 37.062062] bond_newlink+0x49/0xa0 [ 37.065724] ? bond_changelink+0x2360/0x2360 [ 37.070130] rtnl_newlink+0xef4/0x1d50 [ 37.074017] ? rtnl_link_unregister+0x390/0x390 [ 37.078682] ? print_usage_bug+0xc0/0xc0 [ 37.082752] ? __lock_acquire+0x7fc/0x5020 [ 37.086994] ? print_usage_bug+0xc0/0xc0 [ 37.091064] ? graph_lock+0x170/0x170 [ 37.094865] ? print_usage_bug+0xc0/0xc0 [ 37.098937] ? mark_held_locks+0x160/0x160 [ 37.103166] ? __lock_acquire+0x7fc/0x5020 [ 37.107460] ? lock_acquire+0x1e4/0x4f0 [ 37.111435] ? rtnetlink_rcv_msg+0x412/0xc30 [ 37.115849] ? lock_release+0x9f0/0x9f0 [ 37.119843] ? check_same_owner+0x340/0x340 [ 37.124184] ? mutex_trylock+0x2b0/0x2b0 [ 37.128406] ? __lock_acquire+0x7fc/0x5020 [ 37.132644] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 37.138181] ? refcount_sub_and_test_checked+0x21a/0x350 [ 37.143685] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 37.149267] ? rtnl_get_link+0x170/0x370 [ 37.153324] ? rtnl_dump_all+0x600/0x600 [ 37.157402] ? rcu_is_watching+0x8c/0x150 [ 37.161564] ? rtnl_link_unregister+0x390/0x390 [ 37.166256] rtnetlink_rcv_msg+0x46e/0xc30 [ 37.170490] ? rtnetlink_put_metrics+0x690/0x690 [ 37.175263] netlink_rcv_skb+0x172/0x440 [ 37.179326] ? rtnetlink_put_metrics+0x690/0x690 [ 37.184165] ? netlink_ack+0xbe0/0xbe0 [ 37.188055] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 37.192727] rtnetlink_rcv+0x1c/0x20 [ 37.196441] netlink_unicast+0x5a0/0x760 [ 37.200643] ? netlink_attachskb+0x9a0/0x9a0 [ 37.205054] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 37.210591] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 37.215607] netlink_sendmsg+0xa18/0xfc0 [ 37.219822] ? netlink_unicast+0x760/0x760 [ 37.224087] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 37.229015] ? apparmor_socket_sendmsg+0x29/0x30 [ 37.233891] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 37.239447] ? security_socket_sendmsg+0x94/0xc0 [ 37.244242] ? netlink_unicast+0x760/0x760 [ 37.248557] sock_sendmsg+0xd5/0x120 [ 37.252291] ___sys_sendmsg+0x7fd/0x930 [ 37.256294] ? copy_msghdr_from_user+0x580/0x580 [ 37.261052] ? lock_downgrade+0x8f0/0x8f0 [ 37.265234] ? __fget_light+0x2f7/0x440 [ 37.269247] ? fget_raw+0x20/0x20 [ 37.272859] ? __fd_install+0x2db/0x880 [ 37.276939] ? get_unused_fd_flags+0x1a0/0x1a0 [ 37.281610] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 37.287146] ? sockfd_lookup_light+0xc5/0x160 [ 37.291707] __sys_sendmsg+0x11d/0x290 [ 37.295602] ? __ia32_sys_shutdown+0x80/0x80 [ 37.300025] ? __x64_sys_futex+0x47f/0x6a0 [ 37.304272] ? do_syscall_64+0x9a/0x820 [ 37.308277] ? do_syscall_64+0x9a/0x820 [ 37.312271] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 37.317468] ? trace_hardirqs_off+0xb8/0x2b0 [ 37.321894] __x64_sys_sendmsg+0x78/0xb0 [ 37.325957] do_syscall_64+0x1b9/0x820 [ 37.329856] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 37.335262] ? syscall_return_slowpath+0x5e0/0x5e0 [ 37.340191] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 37.345270] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 37.350287] ? recalc_sigpending_tsk+0x180/0x180 [ 37.355159] ? kasan_check_write+0x14/0x20 [ 37.359456] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 37.364315] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 37.369518] RIP: 0033:0x457099 [ 37.372712] 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 0f 1f 84 00 00 00 00 [ 37.391612] RSP: 002b:00007effbf73dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 37.399318] RAX: ffffffffffffffda RBX: 00007effbf73e6d4 RCX: 0000000000457099 [ 37.406594] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 37.413882] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 37.421152] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000fffffff