[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.862189] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 23.939690] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.159888] random: sshd: uninitialized urandom read (32 bytes read) [ 24.661061] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.48' (ECDSA) to the list of known hosts. [ 30.347878] urandom_read: 1 callbacks suppressed [ 30.347883] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/31 02:05:21 parsed 1 programs [ 31.439205] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/31 02:05:23 executed programs: 0 [ 32.630895] IPVS: ftp: loaded support on port[0] = 21 [ 32.843892] bridge0: port 1(bridge_slave_0) entered blocking state [ 32.850326] bridge0: port 1(bridge_slave_0) entered disabled state [ 32.857785] device bridge_slave_0 entered promiscuous mode [ 32.874190] bridge0: port 2(bridge_slave_1) entered blocking state [ 32.880549] bridge0: port 2(bridge_slave_1) entered disabled state [ 32.887846] device bridge_slave_1 entered promiscuous mode [ 32.903662] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.920014] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.963617] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 32.981848] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 33.044578] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 33.051988] team0: Port device team_slave_0 added [ 33.066617] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 33.074020] team0: Port device team_slave_1 added [ 33.090658] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 33.108120] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 33.125238] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 33.143190] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 33.266363] bridge0: port 2(bridge_slave_1) entered blocking state [ 33.272836] bridge0: port 2(bridge_slave_1) entered forwarding state [ 33.279840] bridge0: port 1(bridge_slave_0) entered blocking state [ 33.286238] bridge0: port 1(bridge_slave_0) entered forwarding state [ 33.714865] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 33.721088] 8021q: adding VLAN 0 to HW filter on device bond0 [ 33.762656] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 33.805602] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 33.813038] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 33.852473] 8021q: adding VLAN 0 to HW filter on device team0 [ 34.113246] [ 34.114988] ====================================================== [ 34.121290] WARNING: possible circular locking dependency detected [ 34.127579] 4.19.0-rc1+ #215 Not tainted [ 34.131609] ------------------------------------------------------ [ 34.137901] syz-executor0/4945 is trying to acquire lock: [ 34.143413] 0000000000f04c91 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 34.152674] [ 34.152674] but task is already holding lock: [ 34.158625] 0000000070cc4c22 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 34.166333] [ 34.166333] which lock already depends on the new lock. [ 34.166333] [ 34.174630] [ 34.174630] the existing dependency chain (in reverse order) is: [ 34.182247] [ 34.182247] -> #2 (rtnl_mutex){+.+.}: [ 34.187515] __mutex_lock+0x171/0x1700 [ 34.191985] mutex_lock_nested+0x16/0x20 [ 34.196551] rtnl_lock+0x17/0x20 [ 34.200451] bond_netdev_notify_work+0x44/0xd0 [ 34.205590] process_one_work+0xc73/0x1aa0 [ 34.210331] worker_thread+0x189/0x13c0 [ 34.214819] kthread+0x35a/0x420 [ 34.218765] ret_from_fork+0x3a/0x50 [ 34.222974] [ 34.222974] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 34.230667] process_one_work+0xc0b/0x1aa0 [ 34.235400] worker_thread+0x189/0x13c0 [ 34.239873] kthread+0x35a/0x420 [ 34.243748] ret_from_fork+0x3a/0x50 [ 34.248063] [ 34.248063] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 34.254993] lock_acquire+0x1e4/0x4f0 [ 34.259289] flush_workqueue+0x30a/0x1e10 [ 34.263933] drain_workqueue+0x2a9/0x640 [ 34.268509] destroy_workqueue+0xc6/0x9d0 [ 34.273158] __alloc_workqueue_key+0xef9/0x1190 [ 34.278326] bond_init+0x269/0x940 [ 34.282368] register_netdevice+0x337/0x1100 [ 34.287405] bond_newlink+0x49/0xa0 [ 34.291648] rtnl_newlink+0xef4/0x1d50 [ 34.296068] rtnetlink_rcv_msg+0x46e/0xc30 [ 34.300802] netlink_rcv_skb+0x172/0x440 [ 34.305359] rtnetlink_rcv+0x1c/0x20 [ 34.309573] netlink_unicast+0x5a0/0x760 [ 34.314152] netlink_sendmsg+0xa18/0xfc0 [ 34.318711] sock_sendmsg+0xd5/0x120 [ 34.322925] ___sys_sendmsg+0x7fd/0x930 [ 34.327507] __sys_sendmsg+0x11d/0x290 [ 34.331990] __x64_sys_sendmsg+0x78/0xb0 [ 34.336553] do_syscall_64+0x1b9/0x820 [ 34.340938] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.346621] [ 34.346621] other info that might help us debug this: [ 34.346621] [ 34.354744] Chain exists of: [ 34.354744] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 34.354744] [ 34.368430] Possible unsafe locking scenario: [ 34.368430] [ 34.374463] CPU0 CPU1 [ 34.379099] ---- ---- [ 34.383735] lock(rtnl_mutex); [ 34.386991] lock((work_completion)(&(&nnw->work)->work)); [ 34.395320] lock(rtnl_mutex); [ 34.401092] lock((wq_completion)bond_dev->name); [ 34.405995] [ 34.405995] *** DEADLOCK *** [ 34.405995] [ 34.412043] 1 lock held by syz-executor0/4945: [ 34.416608] #0: 0000000070cc4c22 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 34.424751] [ 34.424751] stack backtrace: [ 34.429227] CPU: 1 PID: 4945 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #215 [ 34.436480] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 34.445947] Call Trace: [ 34.448519] dump_stack+0x1c9/0x2b4 [ 34.452151] ? dump_stack_print_info.cold.2+0x52/0x52 [ 34.457336] ? vprintk_func+0x81/0x117 [ 34.461205] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 34.466998] ? save_trace+0xe0/0x290 [ 34.470700] __lock_acquire+0x3449/0x5020 [ 34.474838] ? mark_held_locks+0x160/0x160 [ 34.479051] ? mark_held_locks+0x160/0x160 [ 34.483262] ? __lock_is_held+0xb5/0x140 [ 34.487300] ? __account_cfs_rq_runtime+0x770/0x770 [ 34.492299] ? set_next_entity+0x2f0/0xa80 [ 34.496514] lock_acquire+0x1e4/0x4f0 [ 34.500291] ? flush_workqueue+0x2db/0x1e10 [ 34.504593] ? lock_release+0x9f0/0x9f0 [ 34.508544] ? lockdep_init_map+0x9/0x10 [ 34.512584] ? __init_waitqueue_head+0x9e/0x150 [ 34.517238] ? init_wait_entry+0x1c0/0x1c0 [ 34.521451] flush_workqueue+0x30a/0x1e10 [ 34.525594] ? flush_workqueue+0x2db/0x1e10 [ 34.529935] ? lock_acquire+0x1e4/0x4f0 [ 34.533914] ? drain_workqueue+0xa9/0x640 [ 34.538045] ? lock_release+0x9f0/0x9f0 [ 34.542214] ? check_same_owner+0x340/0x340 [ 34.546515] ? __queue_delayed_work+0x390/0x390 [ 34.551161] ? graph_lock+0x170/0x170 [ 34.554939] ? kasan_check_write+0x14/0x20 [ 34.559148] ? __mutex_lock+0x6d0/0x1700 [ 34.563189] ? _raw_spin_unlock_irq+0x27/0x70 [ 34.567753] ? drain_workqueue+0xa9/0x640 [ 34.571991] ? finish_task_switch+0x1d3/0x870 [ 34.576468] ? finish_task_switch+0x18a/0x870 [ 34.580944] ? __switch_to_asm+0x34/0x70 [ 34.584986] ? find_held_lock+0x36/0x1c0 [ 34.589033] ? lock_downgrade+0x8f0/0x8f0 [ 34.593160] ? __schedule+0x884/0x1df0 [ 34.597029] ? graph_lock+0x170/0x170 [ 34.600828] ? find_held_lock+0x36/0x1c0 [ 34.604874] ? kasan_check_write+0x14/0x20 [ 34.609093] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 34.614001] ? wait_for_completion+0x8d0/0x8d0 [ 34.618572] ? do_raw_spin_unlock+0xa7/0x2f0 [ 34.622963] ? trace_hardirqs_on+0x2c0/0x2c0 [ 34.627347] drain_workqueue+0x2a9/0x640 [ 34.631400] ? drain_workqueue+0x2a9/0x640 [ 34.635629] ? flush_workqueue+0x1e10/0x1e10 [ 34.640026] ? save_stack+0xa9/0xd0 [ 34.643635] ? save_stack+0x43/0xd0 [ 34.647243] ? __kasan_slab_free+0x11a/0x170 [ 34.651642] ? kasan_slab_free+0xe/0x10 [ 34.655592] ? print_usage_bug+0xc0/0xc0 [ 34.659627] ? bond_init+0x269/0x940 [ 34.663319] ? register_netdevice+0x337/0x1100 [ 34.667886] ? bond_newlink+0x49/0xa0 [ 34.671682] ? rtnl_newlink+0xef4/0x1d50 [ 34.675742] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 34.680126] ? netlink_rcv_skb+0x172/0x440 [ 34.684335] ? rtnetlink_rcv+0x1c/0x20 [ 34.688200] ? netlink_unicast+0x5a0/0x760 [ 34.692420] ? netlink_sendmsg+0xa18/0xfc0 [ 34.696638] ? sock_sendmsg+0xd5/0x120 [ 34.700523] destroy_workqueue+0xc6/0x9d0 [ 34.704679] ? kasan_check_write+0x14/0x20 [ 34.708895] ? wq_watchdog_timer_fn+0x830/0x830 [ 34.713553] ? mark_held_locks+0xc9/0x160 [ 34.717681] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 34.722763] ? kfree+0x111/0x210 [ 34.726108] ? kfree+0x111/0x210 [ 34.729455] ? lockdep_hardirqs_on+0x421/0x5c0 [ 34.734017] ? trace_hardirqs_on+0xbd/0x2c0 [ 34.738320] ? init_rescuer.part.26+0x155/0x190 [ 34.742966] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 34.748048] ? __kasan_slab_free+0x131/0x170 [ 34.752441] ? init_rescuer.part.26+0x155/0x190 [ 34.757096] __alloc_workqueue_key+0xef9/0x1190 [ 34.761747] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.767267] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 34.772274] ? put_dec+0xf0/0xf0 [ 34.775625] ? format_decode+0x1b1/0xaf0 [ 34.779669] ? set_precision+0xe0/0xe0 [ 34.783539] ? simple_strtoll+0xa0/0xa0 [ 34.787502] ? graph_lock+0x170/0x170 [ 34.791305] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 34.796845] ? vsnprintf+0x20d/0x1b60 [ 34.800658] ? find_held_lock+0x36/0x1c0 [ 34.804708] ? lock_downgrade+0x8f0/0x8f0 [ 34.808835] ? kasan_check_read+0x11/0x20 [ 34.812964] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 34.817623] bond_init+0x269/0x940 [ 34.821145] ? __dev_get_by_name+0x170/0x170 [ 34.825600] ? bond_arp_rcv+0x11c0/0x11c0 [ 34.829733] ? check_same_owner+0x340/0x340 [ 34.834032] ? rcu_note_context_switch+0x680/0x680 [ 34.838969] ? bond_arp_rcv+0x11c0/0x11c0 [ 34.843099] register_netdevice+0x337/0x1100 [ 34.847495] ? netdev_change_features+0x110/0x110 [ 34.852356] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.858001] ? ns_capable_common+0x13f/0x170 [ 34.862474] ? ns_capable+0x22/0x30 [ 34.866092] bond_newlink+0x49/0xa0 [ 34.869699] ? bond_changelink+0x2360/0x2360 [ 34.874087] rtnl_newlink+0xef4/0x1d50 [ 34.877960] ? rtnl_link_unregister+0x390/0x390 [ 34.882611] ? print_usage_bug+0xc0/0xc0 [ 34.886660] ? print_usage_bug+0xc0/0xc0 [ 34.890701] ? graph_lock+0x170/0x170 [ 34.894481] ? print_usage_bug+0xc0/0xc0 [ 34.898543] ? mark_held_locks+0x160/0x160 [ 34.902764] ? __lock_acquire+0x7fc/0x5020 [ 34.906989] ? lock_acquire+0x1e4/0x4f0 [ 34.910956] ? rtnetlink_rcv_msg+0x412/0xc30 [ 34.915346] ? lock_release+0x9f0/0x9f0 [ 34.919300] ? check_same_owner+0x340/0x340 [ 34.923610] ? mutex_trylock+0x2b0/0x2b0 [ 34.927652] ? __lock_acquire+0x7fc/0x5020 [ 34.931871] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.937388] ? refcount_sub_and_test_checked+0x21a/0x350 [ 34.942840] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 34.948367] ? rtnl_get_link+0x170/0x370 [ 34.952431] ? rtnl_dump_all+0x600/0x600 [ 34.956475] ? rcu_is_watching+0x8c/0x150 [ 34.960614] ? rtnl_link_unregister+0x390/0x390 [ 34.965262] rtnetlink_rcv_msg+0x46e/0xc30 [ 34.969477] ? rtnetlink_put_metrics+0x690/0x690 [ 34.974226] netlink_rcv_skb+0x172/0x440 [ 34.978281] ? rtnetlink_put_metrics+0x690/0x690 [ 34.983031] ? netlink_ack+0xbe0/0xbe0 [ 34.986901] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 34.991559] rtnetlink_rcv+0x1c/0x20 [ 34.995254] netlink_unicast+0x5a0/0x760 [ 34.999321] ? netlink_attachskb+0x9a0/0x9a0 [ 35.003714] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.009236] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 35.014383] netlink_sendmsg+0xa18/0xfc0 [ 35.018435] ? netlink_unicast+0x760/0x760 [ 35.022654] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 35.027600] ? apparmor_socket_sendmsg+0x29/0x30 [ 35.032338] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.037866] ? security_socket_sendmsg+0x94/0xc0 [ 35.042602] ? netlink_unicast+0x760/0x760 [ 35.046821] sock_sendmsg+0xd5/0x120 [ 35.050530] ___sys_sendmsg+0x7fd/0x930 [ 35.054510] ? copy_msghdr_from_user+0x580/0x580 [ 35.059261] ? __fget_light+0x2f7/0x440 [ 35.063367] ? fget_raw+0x20/0x20 [ 35.066810] ? mon_bin_get_event+0x460/0x460 [ 35.071206] ? mon_bin_get_event+0x460/0x460 [ 35.075599] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.081118] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 35.086639] ? sockfd_lookup_light+0xc5/0x160 [ 35.091116] __sys_sendmsg+0x11d/0x290 [ 35.095034] ? __ia32_sys_shutdown+0x80/0x80 [ 35.099430] ? __x64_sys_futex+0x47f/0x6a0 [ 35.103652] ? do_syscall_64+0x9a/0x820 [ 35.107608] ? do_syscall_64+0x9a/0x820 [ 35.111576] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 35.116664] ? ksys_ioctl+0x81/0xd0 [ 35.120296] __x64_sys_sendmsg+0x78/0xb0 [ 35.124341] do_syscall_64+0x1b9/0x820 [ 35.128209] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 35.133559] ? syscall_return_slowpath+0x5e0/0x5e0 [ 35.138473] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 35.143484] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 35.148500] ? recalc_sigpending_tsk+0x180/0x180 [ 35.153249] ? kasan_check_write+0x14/0x20 [ 35.157465] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 35.162317] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.167493] RIP: 0033:0x457089 [ 35.170682] 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 [ 35.189572] RSP: 002b:00007fcf5c6ddc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 35.197261] RAX: ffffffffffffffda RBX: 00007fcf5c6de6d4 RCX: 0000000000457089 [ 35.204524] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000006 [ 35.211789] RBP: 00000000009300a0 R08: 0000000000000000 R09: 00000000000