[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.579350] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 24.937886] random: sshd: uninitialized urandom read (32 bytes read) [ 25.301576] random: sshd: uninitialized urandom read (32 bytes read) [ 25.857054] random: sshd: uninitialized urandom read (32 bytes read) [ 26.039481] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.37' (ECDSA) to the list of known hosts. [ 31.632030] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/04 10:11:17 parsed 1 programs [ 32.841182] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/04 10:11:18 executed programs: 0 [ 34.001870] IPVS: ftp: loaded support on port[0] = 21 [ 34.224943] bridge0: port 1(bridge_slave_0) entered blocking state [ 34.231477] bridge0: port 1(bridge_slave_0) entered disabled state [ 34.239156] device bridge_slave_0 entered promiscuous mode [ 34.256965] bridge0: port 2(bridge_slave_1) entered blocking state [ 34.263408] bridge0: port 2(bridge_slave_1) entered disabled state [ 34.270838] device bridge_slave_1 entered promiscuous mode [ 34.288475] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.306738] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 34.353676] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 34.373700] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 34.443404] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 34.451082] team0: Port device team_slave_0 added [ 34.467387] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 34.474638] team0: Port device team_slave_1 added [ 34.491070] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 34.509612] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 34.529085] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.548248] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.684360] bridge0: port 2(bridge_slave_1) entered blocking state [ 34.690833] bridge0: port 2(bridge_slave_1) entered forwarding state [ 34.697860] bridge0: port 1(bridge_slave_0) entered blocking state [ 34.704236] bridge0: port 1(bridge_slave_0) entered forwarding state [ 35.188303] 8021q: adding VLAN 0 to HW filter on device bond0 [ 35.238628] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 35.289629] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 35.295810] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 35.306124] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 35.350371] 8021q: adding VLAN 0 to HW filter on device team0 [ 35.667088] [ 35.668762] ====================================================== [ 35.675076] WARNING: possible circular locking dependency detected [ 35.681401] 4.19.0-rc2+ #220 Not tainted [ 35.685471] ------------------------------------------------------ [ 35.691783] syz-executor0/4927 is trying to acquire lock: [ 35.697326] 00000000c8f299f7 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 35.706615] [ 35.706615] but task is already holding lock: [ 35.712600] 0000000035b21b0f (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 35.720327] [ 35.720327] which lock already depends on the new lock. [ 35.720327] [ 35.728655] [ 35.728655] the existing dependency chain (in reverse order) is: [ 35.736257] [ 35.736257] -> #2 (rtnl_mutex){+.+.}: [ 35.741547] __mutex_lock+0x171/0x1700 [ 35.745955] mutex_lock_nested+0x16/0x20 [ 35.750531] rtnl_lock+0x17/0x20 [ 35.754419] bond_netdev_notify_work+0x44/0xd0 [ 35.759516] process_one_work+0xc73/0x1aa0 [ 35.764267] worker_thread+0x189/0x13c0 [ 35.768744] kthread+0x35a/0x420 [ 35.772615] ret_from_fork+0x3a/0x50 [ 35.776832] [ 35.776832] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 35.784601] process_one_work+0xc0b/0x1aa0 [ 35.789339] worker_thread+0x189/0x13c0 [ 35.793830] kthread+0x35a/0x420 [ 35.797706] ret_from_fork+0x3a/0x50 [ 35.801932] [ 35.801932] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 35.808852] lock_acquire+0x1e4/0x4f0 [ 35.813159] flush_workqueue+0x30a/0x1e10 [ 35.817810] drain_workqueue+0x2a9/0x640 [ 35.822377] destroy_workqueue+0xc6/0x9d0 [ 35.827029] __alloc_workqueue_key+0xef9/0x1190 [ 35.832213] bond_init+0x269/0x940 [ 35.836267] register_netdevice+0x337/0x1100 [ 35.841190] bond_newlink+0x49/0xa0 [ 35.845326] rtnl_newlink+0xef4/0x1d50 [ 35.849720] rtnetlink_rcv_msg+0x46e/0xc30 [ 35.854460] netlink_rcv_skb+0x172/0x440 [ 35.859059] rtnetlink_rcv+0x1c/0x20 [ 35.863283] netlink_unicast+0x5a0/0x760 [ 35.867847] netlink_sendmsg+0xa18/0xfc0 [ 35.872415] sock_sendmsg+0xd5/0x120 [ 35.876646] ___sys_sendmsg+0x7fd/0x930 [ 35.881125] __sys_sendmsg+0x11d/0x290 [ 35.885525] __x64_sys_sendmsg+0x78/0xb0 [ 35.890125] do_syscall_64+0x1b9/0x820 [ 35.894530] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.900229] [ 35.900229] other info that might help us debug this: [ 35.900229] [ 35.908363] Chain exists of: [ 35.908363] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 35.908363] [ 35.922066] Possible unsafe locking scenario: [ 35.922066] [ 35.928130] CPU0 CPU1 [ 35.932775] ---- ---- [ 35.937424] lock(rtnl_mutex); [ 35.940683] lock((work_completion)(&(&nnw->work)->work)); [ 35.948892] lock(rtnl_mutex); [ 35.954697] lock((wq_completion)bond_dev->name); [ 35.959618] [ 35.959618] *** DEADLOCK *** [ 35.959618] [ 35.965663] 1 lock held by syz-executor0/4927: [ 35.970254] #0: 0000000035b21b0f (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 35.978400] [ 35.978400] stack backtrace: [ 35.982880] CPU: 1 PID: 4927 Comm: syz-executor0 Not tainted 4.19.0-rc2+ #220 [ 35.990131] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.999467] Call Trace: [ 36.002067] dump_stack+0x1c9/0x2b4 [ 36.005686] ? dump_stack_print_info.cold.2+0x52/0x52 [ 36.010872] ? vprintk_func+0x81/0x117 [ 36.014750] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 36.020460] ? save_trace+0xe0/0x290 [ 36.024177] __lock_acquire+0x3449/0x5020 [ 36.028310] ? mark_held_locks+0x160/0x160 [ 36.032534] ? __lock_is_held+0xb5/0x140 [ 36.036609] ? update_curr+0x344/0xba0 [ 36.040485] ? print_usage_bug+0xc0/0xc0 [ 36.044545] ? pick_next_task_fair+0x999/0x16e0 [ 36.049205] ? find_held_lock+0x36/0x1c0 [ 36.053250] ? mark_held_locks+0xc9/0x160 [ 36.057390] lock_acquire+0x1e4/0x4f0 [ 36.061177] ? flush_workqueue+0x2db/0x1e10 [ 36.065483] ? lock_release+0x9f0/0x9f0 [ 36.069454] ? lockdep_init_map+0x9/0x10 [ 36.073536] ? __init_waitqueue_head+0x9e/0x150 [ 36.078678] ? init_wait_entry+0x1c0/0x1c0 [ 36.082902] flush_workqueue+0x30a/0x1e10 [ 36.087031] ? flush_workqueue+0x2db/0x1e10 [ 36.091347] ? lock_acquire+0x1e4/0x4f0 [ 36.095303] ? drain_workqueue+0xa9/0x640 [ 36.099433] ? lock_release+0x9f0/0x9f0 [ 36.103393] ? check_same_owner+0x340/0x340 [ 36.107699] ? __schedule+0x884/0x1df0 [ 36.111581] ? __queue_delayed_work+0x390/0x390 [ 36.116235] ? graph_lock+0x170/0x170 [ 36.120021] ? kasan_check_write+0x14/0x20 [ 36.124256] ? __mutex_lock+0x6d0/0x1700 [ 36.128321] ? drain_workqueue+0xa9/0x640 [ 36.132451] ? graph_lock+0x170/0x170 [ 36.136237] ? print_usage_bug+0xc0/0xc0 [ 36.140283] ? find_held_lock+0x36/0x1c0 [ 36.144362] ? lock_downgrade+0x8f0/0x8f0 [ 36.148537] ? schedule+0xfb/0x450 [ 36.152098] ? graph_lock+0x170/0x170 [ 36.155908] ? find_held_lock+0x36/0x1c0 [ 36.159977] ? kasan_check_write+0x14/0x20 [ 36.164206] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 36.169122] ? wait_for_completion+0x8d0/0x8d0 [ 36.173691] ? do_raw_spin_unlock+0xa7/0x2f0 [ 36.178085] ? trace_hardirqs_on+0x2c0/0x2c0 [ 36.182478] drain_workqueue+0x2a9/0x640 [ 36.186540] ? drain_workqueue+0x2a9/0x640 [ 36.190793] ? flush_workqueue+0x1e10/0x1e10 [ 36.195195] ? save_stack+0xa9/0xd0 [ 36.198806] ? save_stack+0x43/0xd0 [ 36.202415] ? __kasan_slab_free+0x11a/0x170 [ 36.206805] ? kasan_slab_free+0xe/0x10 [ 36.210764] ? print_usage_bug+0xc0/0xc0 [ 36.214807] ? bond_init+0x269/0x940 [ 36.218514] ? register_netdevice+0x337/0x1100 [ 36.223094] ? bond_newlink+0x49/0xa0 [ 36.226878] ? rtnl_newlink+0xef4/0x1d50 [ 36.230920] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 36.235311] ? netlink_rcv_skb+0x172/0x440 [ 36.239551] ? rtnetlink_rcv+0x1c/0x20 [ 36.243448] ? netlink_unicast+0x5a0/0x760 [ 36.247667] ? netlink_sendmsg+0xa18/0xfc0 [ 36.251906] ? sock_sendmsg+0xd5/0x120 [ 36.255787] destroy_workqueue+0xc6/0x9d0 [ 36.259939] ? kasan_check_write+0x14/0x20 [ 36.264165] ? wq_watchdog_timer_fn+0x830/0x830 [ 36.268823] ? mark_held_locks+0xc9/0x160 [ 36.272954] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 36.278037] ? kfree+0x111/0x210 [ 36.281400] ? kfree+0x111/0x210 [ 36.284766] ? lockdep_hardirqs_on+0x421/0x5c0 [ 36.289331] ? trace_hardirqs_on+0xbd/0x2c0 [ 36.293638] ? init_rescuer.part.26+0x155/0x190 [ 36.298289] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.303377] ? __kasan_slab_free+0x131/0x170 [ 36.307771] ? init_rescuer.part.26+0x155/0x190 [ 36.312433] __alloc_workqueue_key+0xef9/0x1190 [ 36.317090] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.322613] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 36.327617] ? put_dec+0xf0/0xf0 [ 36.330965] ? format_decode+0x1b1/0xaf0 [ 36.335020] ? set_precision+0xe0/0xe0 [ 36.338931] ? simple_strtoll+0xa0/0xa0 [ 36.342889] ? graph_lock+0x170/0x170 [ 36.346675] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.352195] ? vsnprintf+0x20d/0x1b60 [ 36.355981] ? find_held_lock+0x36/0x1c0 [ 36.360064] ? lock_downgrade+0x8f0/0x8f0 [ 36.364232] ? kasan_check_read+0x11/0x20 [ 36.368368] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.373026] bond_init+0x269/0x940 [ 36.376585] ? __dev_get_by_name+0x170/0x170 [ 36.380980] ? bond_arp_rcv+0x11c0/0x11c0 [ 36.385114] ? check_same_owner+0x340/0x340 [ 36.389423] ? rcu_note_context_switch+0x680/0x680 [ 36.394337] ? bond_arp_rcv+0x11c0/0x11c0 [ 36.398487] register_netdevice+0x337/0x1100 [ 36.402911] ? netdev_change_features+0x110/0x110 [ 36.407747] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.413268] ? ns_capable_common+0x13f/0x170 [ 36.417663] bond_newlink+0x49/0xa0 [ 36.421287] ? bond_changelink+0x2360/0x2360 [ 36.425711] rtnl_newlink+0xef4/0x1d50 [ 36.429602] ? rtnl_link_unregister+0x390/0x390 [ 36.434257] ? print_usage_bug+0xc0/0xc0 [ 36.438303] ? print_usage_bug+0xc0/0xc0 [ 36.442347] ? graph_lock+0x170/0x170 [ 36.446129] ? print_usage_bug+0xc0/0xc0 [ 36.450174] ? mark_held_locks+0x160/0x160 [ 36.454392] ? __lock_acquire+0x7fc/0x5020 [ 36.458613] ? lock_acquire+0x1e4/0x4f0 [ 36.462579] ? rtnetlink_rcv_msg+0x412/0xc30 [ 36.466979] ? lock_release+0x9f0/0x9f0 [ 36.470941] ? check_same_owner+0x340/0x340 [ 36.475255] ? mutex_trylock+0x2b0/0x2b0 [ 36.479299] ? __lock_acquire+0x7fc/0x5020 [ 36.483529] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.489071] ? refcount_sub_and_test_checked+0x21a/0x350 [ 36.494528] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.500070] ? rtnl_get_link+0x170/0x370 [ 36.504117] ? rtnl_dump_all+0x600/0x600 [ 36.508163] ? rcu_is_watching+0x8c/0x150 [ 36.512296] ? rtnl_link_unregister+0x390/0x390 [ 36.516948] rtnetlink_rcv_msg+0x46e/0xc30 [ 36.521165] ? rtnetlink_put_metrics+0x690/0x690 [ 36.525921] netlink_rcv_skb+0x172/0x440 [ 36.529969] ? rtnetlink_put_metrics+0x690/0x690 [ 36.534732] ? netlink_ack+0xbe0/0xbe0 [ 36.538607] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.543260] rtnetlink_rcv+0x1c/0x20 [ 36.546957] netlink_unicast+0x5a0/0x760 [ 36.551020] ? netlink_attachskb+0x9a0/0x9a0 [ 36.555421] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.560944] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 36.565944] netlink_sendmsg+0xa18/0xfc0 [ 36.569998] ? netlink_unicast+0x760/0x760 [ 36.574219] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 36.579133] ? apparmor_socket_sendmsg+0x29/0x30 [ 36.583891] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.589414] ? security_socket_sendmsg+0x94/0xc0 [ 36.594152] ? netlink_unicast+0x760/0x760 [ 36.598398] sock_sendmsg+0xd5/0x120 [ 36.602100] ___sys_sendmsg+0x7fd/0x930 [ 36.606073] ? copy_msghdr_from_user+0x580/0x580 [ 36.610859] ? lock_downgrade+0x8f0/0x8f0 [ 36.614995] ? __fget_light+0x2f7/0x440 [ 36.619196] ? fget_raw+0x20/0x20 [ 36.622636] ? __fd_install+0x2db/0x880 [ 36.626596] ? get_unused_fd_flags+0x1a0/0x1a0 [ 36.631167] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.636688] ? sockfd_lookup_light+0xc5/0x160 [ 36.641169] __sys_sendmsg+0x11d/0x290 [ 36.645080] ? __ia32_sys_shutdown+0x80/0x80 [ 36.649477] ? __x64_sys_futex+0x47f/0x6a0 [ 36.653708] ? do_syscall_64+0x9a/0x820 [ 36.657705] ? do_syscall_64+0x9a/0x820 [ 36.661664] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.666759] ? trace_hardirqs_off+0xb8/0x2b0 [ 36.671172] __x64_sys_sendmsg+0x78/0xb0 [ 36.675244] do_syscall_64+0x1b9/0x820 [ 36.679137] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 36.684487] ? syscall_return_slowpath+0x5e0/0x5e0 [ 36.689429] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 36.694453] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 36.699457] ? recalc_sigpending_tsk+0x180/0x180 [ 36.704199] ? kasan_check_write+0x14/0x20 [ 36.708419] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 36.713248] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 36.718426] RIP: 0033:0x457099 [ 36.721608] 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 [ 36.740499] RSP: 002b:00007f2c23cc4c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 36.748207] RAX: ffffffffffffffda RBX: 00007f2c23cc56d4 RCX: 0000000000457099 [ 36.755461] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 [ 36.762712] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 36.769963] R10: 00