[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.089006] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 22.614159] random: sshd: uninitialized urandom read (32 bytes read) [ 22.926819] random: sshd: uninitialized urandom read (32 bytes read) [ 23.481591] random: sshd: uninitialized urandom read (32 bytes read) [ 146.241690] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.14' (ECDSA) to the list of known hosts. [ 151.713931] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/07 20:27:23 parsed 1 programs [ 152.941038] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/07 20:27:25 executed programs: 0 [ 154.222939] IPVS: ftp: loaded support on port[0] = 21 [ 154.436510] bridge0: port 1(bridge_slave_0) entered blocking state [ 154.442977] bridge0: port 1(bridge_slave_0) entered disabled state [ 154.450387] device bridge_slave_0 entered promiscuous mode [ 154.467745] bridge0: port 2(bridge_slave_1) entered blocking state [ 154.474141] bridge0: port 2(bridge_slave_1) entered disabled state [ 154.481089] device bridge_slave_1 entered promiscuous mode [ 154.498002] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 154.514877] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 154.558978] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 154.577573] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 154.643887] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 154.651267] team0: Port device team_slave_0 added [ 154.666251] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 154.673407] team0: Port device team_slave_1 added [ 154.689999] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 154.706918] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 154.723919] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 154.741035] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 154.868655] bridge0: port 2(bridge_slave_1) entered blocking state [ 154.875230] bridge0: port 2(bridge_slave_1) entered forwarding state [ 154.882039] bridge0: port 1(bridge_slave_0) entered blocking state [ 154.888401] bridge0: port 1(bridge_slave_0) entered forwarding state [ 155.345526] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 155.351710] 8021q: adding VLAN 0 to HW filter on device bond0 [ 155.399945] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 155.423728] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 155.452973] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 155.459274] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 155.466595] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 155.504933] 8021q: adding VLAN 0 to HW filter on device team0 [ 155.790041] [ 155.791703] ====================================================== [ 155.797995] WARNING: possible circular locking dependency detected [ 155.804290] 4.19.0-rc2+ #226 Not tainted [ 155.808335] ------------------------------------------------------ [ 155.814634] syz-executor0/4558 is trying to acquire lock: [ 155.820147] 000000003114d24b ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 155.829409] [ 155.829409] but task is already holding lock: [ 155.835360] 000000009afa871b (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 155.843066] [ 155.843066] which lock already depends on the new lock. [ 155.843066] [ 155.851365] [ 155.851365] the existing dependency chain (in reverse order) is: [ 155.858963] [ 155.858963] -> #2 (rtnl_mutex){+.+.}: [ 155.864238] __mutex_lock+0x171/0x1700 [ 155.868696] mutex_lock_nested+0x16/0x20 [ 155.873279] rtnl_lock+0x17/0x20 [ 155.877189] bond_netdev_notify_work+0x44/0xd0 [ 155.882286] process_one_work+0xc73/0x1aa0 [ 155.887023] worker_thread+0x189/0x13c0 [ 155.891502] kthread+0x35a/0x420 [ 155.895370] ret_from_fork+0x3a/0x50 [ 155.899644] [ 155.899644] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 155.907383] process_one_work+0xc0b/0x1aa0 [ 155.912122] worker_thread+0x189/0x13c0 [ 155.916602] kthread+0x35a/0x420 [ 155.920476] ret_from_fork+0x3a/0x50 [ 155.924683] [ 155.924683] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 155.931664] lock_acquire+0x1e4/0x4f0 [ 155.935973] flush_workqueue+0x30a/0x1e10 [ 155.940621] drain_workqueue+0x2a9/0x640 [ 155.945184] destroy_workqueue+0xc6/0x9d0 [ 155.949840] __alloc_workqueue_key+0xef9/0x1190 [ 155.955013] bond_init+0x269/0x940 [ 155.959054] register_netdevice+0x337/0x1100 [ 155.964103] bond_newlink+0x49/0xa0 [ 155.968236] rtnl_newlink+0xef4/0x1d50 [ 155.972623] rtnetlink_rcv_msg+0x46e/0xc30 [ 155.977358] netlink_rcv_skb+0x172/0x440 [ 155.981917] rtnetlink_rcv+0x1c/0x20 [ 155.986134] netlink_unicast+0x5a0/0x760 [ 155.990697] netlink_sendmsg+0xa18/0xfc0 [ 155.995257] sock_sendmsg+0xd5/0x120 [ 155.999536] ___sys_sendmsg+0x7fd/0x930 [ 156.004018] __sys_sendmsg+0x11d/0x290 [ 156.008448] __x64_sys_sendmsg+0x78/0xb0 [ 156.013025] do_syscall_64+0x1b9/0x820 [ 156.017481] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 156.023175] [ 156.023175] other info that might help us debug this: [ 156.023175] [ 156.031322] Chain exists of: [ 156.031322] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 156.031322] [ 156.045141] Possible unsafe locking scenario: [ 156.045141] [ 156.051183] CPU0 CPU1 [ 156.055866] ---- ---- [ 156.060587] lock(rtnl_mutex); [ 156.063852] lock((work_completion)(&(&nnw->work)->work)); [ 156.072094] lock(rtnl_mutex); [ 156.077879] lock((wq_completion)bond_dev->name); [ 156.082789] [ 156.082789] *** DEADLOCK *** [ 156.082789] [ 156.088827] 1 lock held by syz-executor0/4558: [ 156.093385] #0: 000000009afa871b (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 156.101522] [ 156.101522] stack backtrace: [ 156.105999] CPU: 1 PID: 4558 Comm: syz-executor0 Not tainted 4.19.0-rc2+ #226 [ 156.113249] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 156.122579] Call Trace: [ 156.125153] dump_stack+0x1c9/0x2b4 [ 156.128760] ? dump_stack_print_info.cold.2+0x52/0x52 [ 156.133941] ? vprintk_func+0x81/0x117 [ 156.137811] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 156.143501] ? save_trace+0xe0/0x290 [ 156.147196] __lock_acquire+0x3449/0x5020 [ 156.151327] ? mark_held_locks+0x160/0x160 [ 156.155548] ? mark_held_locks+0x160/0x160 [ 156.159764] ? __lock_is_held+0xb5/0x140 [ 156.163813] ? __account_cfs_rq_runtime+0x770/0x770 [ 156.168815] ? set_next_entity+0x2f0/0xa80 [ 156.173115] lock_acquire+0x1e4/0x4f0 [ 156.176905] ? flush_workqueue+0x2db/0x1e10 [ 156.181212] ? lock_release+0x9f0/0x9f0 [ 156.185209] ? lockdep_init_map+0x9/0x10 [ 156.189258] ? __init_waitqueue_head+0x9e/0x150 [ 156.193907] ? init_wait_entry+0x1c0/0x1c0 [ 156.198128] flush_workqueue+0x30a/0x1e10 [ 156.202258] ? flush_workqueue+0x2db/0x1e10 [ 156.206559] ? lock_acquire+0x1e4/0x4f0 [ 156.210511] ? drain_workqueue+0xa9/0x640 [ 156.214640] ? lock_release+0x9f0/0x9f0 [ 156.218596] ? check_same_owner+0x340/0x340 [ 156.222907] ? __queue_delayed_work+0x390/0x390 [ 156.227564] ? graph_lock+0x170/0x170 [ 156.231462] ? kasan_check_write+0x14/0x20 [ 156.235683] ? __mutex_lock+0x6d0/0x1700 [ 156.239727] ? drain_workqueue+0xa9/0x640 [ 156.243858] ? finish_task_switch+0x2ca/0x870 [ 156.248524] ? find_held_lock+0x36/0x1c0 [ 156.252573] ? lock_downgrade+0x8f0/0x8f0 [ 156.256811] ? __schedule+0x884/0x1df0 [ 156.260801] ? graph_lock+0x170/0x170 [ 156.264589] ? find_held_lock+0x36/0x1c0 [ 156.268632] ? kasan_check_write+0x14/0x20 [ 156.272848] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 156.277758] ? wait_for_completion+0x8d0/0x8d0 [ 156.282328] ? do_raw_spin_unlock+0xa7/0x2f0 [ 156.286732] ? trace_hardirqs_on+0x2c0/0x2c0 [ 156.291127] drain_workqueue+0x2a9/0x640 [ 156.295237] ? drain_workqueue+0x2a9/0x640 [ 156.299470] ? flush_workqueue+0x1e10/0x1e10 [ 156.303863] ? save_stack+0xa9/0xd0 [ 156.307474] ? save_stack+0x43/0xd0 [ 156.311082] ? __kasan_slab_free+0x11a/0x170 [ 156.315476] ? kasan_slab_free+0xe/0x10 [ 156.319428] ? print_usage_bug+0xc0/0xc0 [ 156.323471] ? bond_init+0x269/0x940 [ 156.327166] ? register_netdevice+0x337/0x1100 [ 156.331727] ? bond_newlink+0x49/0xa0 [ 156.335511] ? rtnl_newlink+0xef4/0x1d50 [ 156.339553] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 156.343942] ? netlink_rcv_skb+0x172/0x440 [ 156.348157] ? rtnetlink_rcv+0x1c/0x20 [ 156.352039] ? netlink_unicast+0x5a0/0x760 [ 156.356260] ? netlink_sendmsg+0xa18/0xfc0 [ 156.360486] ? sock_sendmsg+0xd5/0x120 [ 156.364360] destroy_workqueue+0xc6/0x9d0 [ 156.368505] ? kasan_check_write+0x14/0x20 [ 156.372743] ? wq_watchdog_timer_fn+0x830/0x830 [ 156.377396] ? mark_held_locks+0xc9/0x160 [ 156.381529] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 156.386617] ? kfree+0x111/0x210 [ 156.390144] ? kfree+0x111/0x210 [ 156.393502] ? lockdep_hardirqs_on+0x421/0x5c0 [ 156.398157] ? trace_hardirqs_on+0xbd/0x2c0 [ 156.402482] ? init_rescuer.part.26+0x155/0x190 [ 156.407136] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 156.412367] ? __kasan_slab_free+0x131/0x170 [ 156.416762] ? init_rescuer.part.26+0x155/0x190 [ 156.421420] __alloc_workqueue_key+0xef9/0x1190 [ 156.426321] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 156.431843] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 156.436867] ? put_dec+0xf0/0xf0 [ 156.440228] ? format_decode+0x1b1/0xaf0 [ 156.444276] ? set_precision+0xe0/0xe0 [ 156.448153] ? simple_strtoll+0xa0/0xa0 [ 156.452120] ? graph_lock+0x170/0x170 [ 156.455909] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 156.463792] ? vsnprintf+0x20d/0x1b60 [ 156.467583] ? find_held_lock+0x36/0x1c0 [ 156.471628] ? lock_downgrade+0x8f0/0x8f0 [ 156.475764] ? kasan_check_read+0x11/0x20 [ 156.479897] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 156.484555] bond_init+0x269/0x940 [ 156.488118] ? __dev_get_by_name+0x170/0x170 [ 156.492531] ? bond_arp_rcv+0x11c0/0x11c0 [ 156.496693] ? check_same_owner+0x340/0x340 [ 156.501020] ? rcu_note_context_switch+0x680/0x680 [ 156.505936] ? bond_arp_rcv+0x11c0/0x11c0 [ 156.510104] register_netdevice+0x337/0x1100 [ 156.514512] ? netdev_change_features+0x110/0x110 [ 156.519343] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 156.524860] ? ns_capable_common+0x13f/0x170 [ 156.529256] ? ns_capable+0x22/0x30 [ 156.532871] bond_newlink+0x49/0xa0 [ 156.536487] ? bond_changelink+0x2360/0x2360 [ 156.540948] rtnl_newlink+0xef4/0x1d50 [ 156.544825] ? rtnl_link_unregister+0x390/0x390 [ 156.549491] ? print_usage_bug+0xc0/0xc0 [ 156.553548] ? __lock_acquire+0x7fc/0x5020 [ 156.557764] ? print_usage_bug+0xc0/0xc0 [ 156.561806] ? graph_lock+0x170/0x170 [ 156.565608] ? print_usage_bug+0xc0/0xc0 [ 156.569839] ? mark_held_locks+0x160/0x160 [ 156.574069] ? __lock_acquire+0x7fc/0x5020 [ 156.579176] ? lock_acquire+0x1e4/0x4f0 [ 156.583149] ? rtnetlink_rcv_msg+0x412/0xc30 [ 156.587546] ? lock_release+0x9f0/0x9f0 [ 156.591507] ? check_same_owner+0x340/0x340 [ 156.595820] ? mutex_trylock+0x2b0/0x2b0 [ 156.599862] ? __lock_acquire+0x7fc/0x5020 [ 156.604108] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 156.609877] ? refcount_sub_and_test_checked+0x21a/0x350 [ 156.615397] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 156.620921] ? rtnl_get_link+0x170/0x370 [ 156.624973] ? rtnl_dump_all+0x600/0x600 [ 156.629030] ? rcu_is_watching+0x8c/0x150 [ 156.633161] ? rtnl_link_unregister+0x390/0x390 [ 156.638032] rtnetlink_rcv_msg+0x46e/0xc30 [ 156.642250] ? rtnetlink_put_metrics+0x690/0x690 [ 156.647000] netlink_rcv_skb+0x172/0x440 [ 156.651067] ? rtnetlink_put_metrics+0x690/0x690 [ 156.655803] ? netlink_ack+0xbe0/0xbe0 [ 156.659695] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 156.664348] rtnetlink_rcv+0x1c/0x20 [ 156.668044] netlink_unicast+0x5a0/0x760 [ 156.672092] ? netlink_attachskb+0x9a0/0x9a0 [ 156.676490] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 156.682022] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 156.687027] netlink_sendmsg+0xa18/0xfc0 [ 156.691073] ? netlink_unicast+0x760/0x760 [ 156.695295] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 156.700215] ? apparmor_socket_sendmsg+0x29/0x30 [ 156.704967] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 156.710515] ? security_socket_sendmsg+0x94/0xc0 [ 156.715267] ? netlink_unicast+0x760/0x760 [ 156.719507] sock_sendmsg+0xd5/0x120 [ 156.723218] ___sys_sendmsg+0x7fd/0x930 [ 156.727219] ? copy_msghdr_from_user+0x580/0x580 [ 156.731993] ? lock_downgrade+0x8f0/0x8f0 [ 156.736133] ? __fget_light+0x2f7/0x440 [ 156.740093] ? fget_raw+0x20/0x20 [ 156.743567] ? __fd_install+0x2db/0x880 [ 156.747536] ? get_unused_fd_flags+0x1a0/0x1a0 [ 156.752118] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 156.757639] ? sockfd_lookup_light+0xc5/0x160 [ 156.762118] __sys_sendmsg+0x11d/0x290 [ 156.765989] ? __ia32_sys_shutdown+0x80/0x80 [ 156.770403] ? __x64_sys_futex+0x47f/0x6a0 [ 156.774622] ? do_syscall_64+0x9a/0x820 [ 156.778581] ? do_syscall_64+0x9a/0x820 [ 156.782563] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 156.787648] ? trace_hardirqs_off+0xb8/0x2c0 [ 156.792048] __x64_sys_sendmsg+0x78/0xb0 [ 156.796105] do_syscall_64+0x1b9/0x820 [ 156.799977] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 156.805363] ? syscall_return_slowpath+0x5e0/0x5e0 [ 156.810276] ? trace_hardirqs_on_caller+0x2c0/0x2c0 [ 156.815494] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 156.820496] ? recalc_sigpending_tsk+0x180/0x180 [ 156.825244] ? kasan_check_write+0x14/0x20 [ 156.829475] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 156.834334] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 156.839525] RIP: 0033:0x457099 [ 156.842705] 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 [ 156.861589] RSP: 002b:00007faa4666ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 156.869325] RAX: ffffffffffffffda RBX: 00007faa4666b6d4 RCX: 0000000000457099 [ 156.876613] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 156.883863] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 156.891113] R10: 0000000000000000 R11: 0000