[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 25.160439] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 25.605040] random: sshd: uninitialized urandom read (32 bytes read) [ 25.983433] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.570325] random: sshd: uninitialized urandom read (32 bytes read) [ 180.773872] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.49' (ECDSA) to the list of known hosts. [ 186.321886] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/11 23:04:48 parsed 1 programs [ 187.408079] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/11 23:04:49 executed programs: 0 [ 188.635073] IPVS: ftp: loaded support on port[0] = 21 [ 188.876512] bridge0: port 1(bridge_slave_0) entered blocking state [ 188.883430] bridge0: port 1(bridge_slave_0) entered disabled state [ 188.890434] device bridge_slave_0 entered promiscuous mode [ 188.908314] bridge0: port 2(bridge_slave_1) entered blocking state [ 188.914754] bridge0: port 2(bridge_slave_1) entered disabled state [ 188.921648] device bridge_slave_1 entered promiscuous mode [ 188.939590] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 188.957202] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 189.007053] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 189.027934] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 189.099949] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 189.107551] team0: Port device team_slave_0 added [ 189.125077] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 189.132830] team0: Port device team_slave_1 added [ 189.149295] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 189.168062] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 189.187217] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 189.206253] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 189.347133] bridge0: port 2(bridge_slave_1) entered blocking state [ 189.353590] bridge0: port 2(bridge_slave_1) entered forwarding state [ 189.360320] bridge0: port 1(bridge_slave_0) entered blocking state [ 189.366740] bridge0: port 1(bridge_slave_0) entered forwarding state [ 189.859462] 8021q: adding VLAN 0 to HW filter on device bond0 [ 189.908448] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 189.959272] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 189.965463] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 189.974236] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 190.020309] 8021q: adding VLAN 0 to HW filter on device team0 [ 190.348287] [ 190.350072] ====================================================== [ 190.356365] WARNING: possible circular locking dependency detected [ 190.362659] 4.19.0-rc2+ #211 Not tainted [ 190.366696] ------------------------------------------------------ [ 190.373012] syz-executor0/5613 is trying to acquire lock: [ 190.378537] 00000000062fc248 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 190.387860] [ 190.387860] but task is already holding lock: [ 190.393818] 0000000002cad25e (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x40e/0xc20 [ 190.401521] [ 190.401521] which lock already depends on the new lock. [ 190.401521] [ 190.409909] [ 190.409909] the existing dependency chain (in reverse order) is: [ 190.417516] [ 190.417516] -> #2 (rtnl_mutex){+.+.}: [ 190.422799] __mutex_lock+0x166/0x1710 [ 190.427189] mutex_lock_nested+0x16/0x20 [ 190.431761] rtnl_lock+0x17/0x20 [ 190.435648] bond_netdev_notify_work+0x44/0xd0 [ 190.440735] process_one_work+0xc90/0x1b90 [ 190.445475] worker_thread+0x17f/0x1390 [ 190.449954] kthread+0x35a/0x420 [ 190.453825] ret_from_fork+0x3a/0x50 [ 190.458033] [ 190.458033] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 190.465734] process_one_work+0xc0a/0x1b90 [ 190.470474] worker_thread+0x17f/0x1390 [ 190.474953] kthread+0x35a/0x420 [ 190.478822] ret_from_fork+0x3a/0x50 [ 190.483031] [ 190.483031] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 190.490282] lock_acquire+0x1ed/0x520 [ 190.494588] flush_workqueue+0x30a/0x1e10 [ 190.499237] drain_workqueue+0x2a9/0x640 [ 190.503800] destroy_workqueue+0xc6/0x9c0 [ 190.508454] __alloc_workqueue_key+0xed8/0x1170 [ 190.513693] bond_init+0x274/0x970 [ 190.517746] register_netdevice+0x332/0x10f0 [ 190.522673] bond_newlink+0x49/0xa0 [ 190.526808] rtnl_newlink+0xec6/0x1d40 [ 190.531314] rtnetlink_rcv_msg+0x46a/0xc20 [ 190.536060] netlink_rcv_skb+0x172/0x440 [ 190.540622] rtnetlink_rcv+0x1c/0x20 [ 190.544933] netlink_unicast+0x5a5/0x760 [ 190.549520] netlink_sendmsg+0xa18/0xfc0 [ 190.554089] sock_sendmsg+0xd5/0x120 [ 190.558304] ___sys_sendmsg+0x7fd/0x930 [ 190.562788] __sys_sendmsg+0x11d/0x280 [ 190.567198] __x64_sys_sendmsg+0x78/0xb0 [ 190.571781] do_syscall_64+0x1b9/0x820 [ 190.576177] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 190.581865] [ 190.581865] other info that might help us debug this: [ 190.581865] [ 190.590004] Chain exists of: [ 190.590004] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 190.590004] [ 190.603695] Possible unsafe locking scenario: [ 190.603695] [ 190.609730] CPU0 CPU1 [ 190.614378] ---- ---- [ 190.619034] lock(rtnl_mutex); [ 190.622295] lock((work_completion)(&(&nnw->work)->work)); [ 190.630501] lock(rtnl_mutex); [ 190.636327] lock((wq_completion)bond_dev->name); [ 190.641288] [ 190.641288] *** DEADLOCK *** [ 190.641288] [ 190.647339] 1 lock held by syz-executor0/5613: [ 190.651903] #0: 0000000002cad25e (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x40e/0xc20 [ 190.660046] [ 190.660046] stack backtrace: [ 190.664704] CPU: 0 PID: 5613 Comm: syz-executor0 Not tainted 4.19.0-rc2+ #211 [ 190.671952] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 190.681285] Call Trace: [ 190.683857] dump_stack+0x1c4/0x2b4 [ 190.687466] ? dump_stack_print_info.cold.2+0x52/0x52 [ 190.692674] ? vprintk_func+0x85/0x181 [ 190.696546] print_circular_bug.isra.33.cold.54+0x1bd/0x27d [ 190.702236] ? save_trace+0xe0/0x290 [ 190.706026] __lock_acquire+0x33e4/0x4ec0 [ 190.710167] ? mark_held_locks+0x130/0x130 [ 190.714389] ? print_usage_bug+0xc0/0xc0 [ 190.718438] ? select_task_rq_fair+0x754/0x34f0 [ 190.723099] ? select_idle_sibling+0xcc/0xe80 [ 190.727589] ? __lock_is_held+0xb5/0x140 [ 190.731640] ? select_task_rq_fair+0x754/0x34f0 [ 190.736291] lock_acquire+0x1ed/0x520 [ 190.740075] ? flush_workqueue+0x2db/0x1e10 [ 190.744381] ? lock_release+0x970/0x970 [ 190.748345] ? lockdep_init_map+0x9/0x10 [ 190.752390] ? __init_waitqueue_head+0x9e/0x150 [ 190.757039] ? init_wait_entry+0x1c0/0x1c0 [ 190.761278] flush_workqueue+0x30a/0x1e10 [ 190.765416] ? flush_workqueue+0x2db/0x1e10 [ 190.769720] ? lock_acquire+0x1ed/0x520 [ 190.773695] ? drain_workqueue+0xa9/0x640 [ 190.777833] ? lock_release+0x970/0x970 [ 190.781840] ? task_change_group_fair+0xa30/0xa30 [ 190.786676] ? flush_rcu_work+0x90/0x90 [ 190.790636] ? graph_lock+0x170/0x170 [ 190.794427] ? __mutex_lock+0x872/0x1710 [ 190.798484] ? rcu_bh_qs+0xc0/0xc0 [ 190.802009] ? drain_workqueue+0xa9/0x640 [ 190.806139] ? graph_lock+0x170/0x170 [ 190.809925] ? find_held_lock+0x36/0x1c0 [ 190.813969] ? drain_workqueue+0x13f/0x640 [ 190.818186] ? lock_downgrade+0x900/0x900 [ 190.822316] ? graph_lock+0x170/0x170 [ 190.826095] ? find_held_lock+0x36/0x1c0 [ 190.830139] ? kasan_check_write+0x14/0x20 [ 190.834361] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 190.839271] ? wait_for_completion+0x8a0/0x8a0 [ 190.843849] ? do_raw_spin_unlock+0xa7/0x2f0 [ 190.848245] drain_workqueue+0x2a9/0x640 [ 190.852291] ? drain_workqueue+0x2a9/0x640 [ 190.856514] ? flush_workqueue+0x1e10/0x1e10 [ 190.860902] ? save_stack+0xa9/0xd0 [ 190.864508] ? save_stack+0x43/0xd0 [ 190.868114] ? __kasan_slab_free+0x102/0x150 [ 190.872505] ? kasan_slab_free+0xe/0x10 [ 190.876462] ? kfree+0xcf/0x230 [ 190.879725] ? print_usage_bug+0xc0/0xc0 [ 190.883767] ? register_netdevice+0x332/0x10f0 [ 190.888337] ? bond_newlink+0x49/0xa0 [ 190.892123] ? rtnl_newlink+0xec6/0x1d40 [ 190.896172] ? rtnetlink_rcv_msg+0x46a/0xc20 [ 190.900562] ? netlink_rcv_skb+0x172/0x440 [ 190.904784] ? rtnetlink_rcv+0x1c/0x20 [ 190.908653] ? netlink_unicast+0x5a5/0x760 [ 190.912870] ? netlink_sendmsg+0xa18/0xfc0 [ 190.917085] ? sock_sendmsg+0xd5/0x120 [ 190.920957] destroy_workqueue+0xc6/0x9c0 [ 190.925093] ? kasan_check_write+0x14/0x20 [ 190.929311] ? wq_watchdog_timer_fn+0x810/0x810 [ 190.933962] ? mark_held_locks+0xc7/0x130 [ 190.938089] ? kfree+0x107/0x230 [ 190.941438] ? kfree+0x107/0x230 [ 190.944807] ? lockdep_hardirqs_on+0x421/0x5c0 [ 190.949378] ? trace_hardirqs_on+0xbd/0x310 [ 190.953687] ? init_rescuer.part.25+0x155/0x190 [ 190.958339] ? __bpf_trace_preemptirq_template+0x30/0x30 [ 190.963770] ? __kasan_slab_free+0x119/0x150 [ 190.968218] ? init_rescuer.part.25+0x155/0x190 [ 190.972874] __alloc_workqueue_key+0xed8/0x1170 [ 190.977528] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 190.982529] ? put_dec+0xf0/0xf0 [ 190.985877] ? format_decode+0x1b2/0xaf0 [ 190.989921] ? set_precision+0xe0/0xe0 [ 190.993820] ? simple_strtoll+0xa0/0xa0 [ 190.997785] ? graph_lock+0x170/0x170 [ 191.001573] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 191.007094] ? find_held_lock+0x36/0x1c0 [ 191.011139] ? lock_downgrade+0x900/0x900 [ 191.015271] ? check_preemption_disabled+0x48/0x200 [ 191.020273] ? rcu_read_unlock_special.part.39+0x11f0/0x11f0 [ 191.026056] ? kasan_check_read+0x11/0x20 [ 191.030189] ? rcu_dynticks_curr_cpu_in_eqs+0x9f/0x160 [ 191.035446] ? rcu_bh_qs+0xc0/0xc0 [ 191.038970] bond_init+0x274/0x970 [ 191.042503] ? __dev_get_by_name+0x170/0x170 [ 191.046901] ? bond_set_rx_mode+0x560/0x560 [ 191.051205] ? rtnl_is_locked+0xb5/0xf0 [ 191.055173] ? bond_set_rx_mode+0x560/0x560 [ 191.059476] register_netdevice+0x332/0x10f0 [ 191.063866] ? netdev_change_features+0x110/0x110 [ 191.068691] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.074211] ? ns_capable_common+0x13f/0x170 [ 191.078603] bond_newlink+0x49/0xa0 [ 191.082212] ? bond_changelink+0x2370/0x2370 [ 191.086603] rtnl_newlink+0xec6/0x1d40 [ 191.090495] ? rtnl_link_unregister+0x390/0x390 [ 191.095156] ? print_usage_bug+0xc0/0xc0 [ 191.099211] ? __lock_acquire+0x7ec/0x4ec0 [ 191.103429] ? print_usage_bug+0xc0/0xc0 [ 191.107471] ? print_usage_bug+0xc0/0xc0 [ 191.111510] ? mark_held_locks+0x130/0x130 [ 191.115727] ? __lock_acquire+0x7ec/0x4ec0 [ 191.119944] ? lock_acquire+0x1ed/0x520 [ 191.123900] ? rtnetlink_rcv_msg+0x40e/0xc20 [ 191.128289] ? lock_release+0x970/0x970 [ 191.132247] ? arch_local_save_flags+0x40/0x40 [ 191.136836] ? mutex_trylock+0x2b0/0x2b0 [ 191.140894] ? __lock_acquire+0x7ec/0x4ec0 [ 191.145114] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.150634] ? refcount_sub_and_test_checked+0x203/0x310 [ 191.156075] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 191.161591] ? rtnl_get_link+0x170/0x370 [ 191.165634] ? rtnl_dump_all+0x570/0x570 [ 191.169677] ? kasan_check_read+0x11/0x20 [ 191.173813] ? rcu_dynticks_curr_cpu_in_eqs+0x9f/0x160 [ 191.179072] ? ns_capable_common+0x13f/0x170 [ 191.183463] ? rtnl_link_unregister+0x390/0x390 [ 191.188113] rtnetlink_rcv_msg+0x46a/0xc20 [ 191.192331] ? rtnetlink_put_metrics+0x690/0x690 [ 191.197075] netlink_rcv_skb+0x172/0x440 [ 191.201115] ? rtnetlink_put_metrics+0x690/0x690 [ 191.205856] ? netlink_ack+0xb80/0xb80 [ 191.209724] rtnetlink_rcv+0x1c/0x20 [ 191.213421] netlink_unicast+0x5a5/0x760 [ 191.217476] ? netlink_attachskb+0x9a0/0x9a0 [ 191.221868] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.227385] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 191.232387] netlink_sendmsg+0xa18/0xfc0 [ 191.236430] ? netlink_unicast+0x760/0x760 [ 191.240732] ? aa_sock_msg_perm.isra.12+0xba/0x160 [ 191.245641] ? apparmor_socket_sendmsg+0x29/0x30 [ 191.250380] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.255902] ? security_socket_sendmsg+0x94/0xc0 [ 191.260640] ? netlink_unicast+0x760/0x760 [ 191.264858] sock_sendmsg+0xd5/0x120 [ 191.268567] ___sys_sendmsg+0x7fd/0x930 [ 191.272530] ? copy_msghdr_from_user+0x580/0x580 [ 191.277267] ? __fd_install+0x2b5/0x8f0 [ 191.281226] ? check_preemption_disabled+0x48/0x200 [ 191.286225] ? __fget_light+0x2e9/0x430 [ 191.290184] ? fget_raw+0x20/0x20 [ 191.293622] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.299138] ? __fd_install+0x2f9/0x8f0 [ 191.303099] ? get_unused_fd_flags+0x1a0/0x1a0 [ 191.307667] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 191.313188] ? sockfd_lookup_light+0xc5/0x160 [ 191.317667] __sys_sendmsg+0x11d/0x280 [ 191.321538] ? __ia32_sys_shutdown+0x80/0x80 [ 191.325959] ? __x64_sys_futex+0x47f/0x6a0 [ 191.330184] ? do_syscall_64+0x9a/0x820 [ 191.334138] ? do_syscall_64+0x9a/0x820 [ 191.338101] ? __bpf_trace_preemptirq_template+0x30/0x30 [ 191.343533] ? trace_hardirqs_off+0xb8/0x300 [ 191.347922] __x64_sys_sendmsg+0x78/0xb0 [ 191.351975] do_syscall_64+0x1b9/0x820 [ 191.355853] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 191.361201] ? syscall_return_slowpath+0x5e0/0x5e0 [ 191.366130] ? trace_hardirqs_off+0x300/0x300 [ 191.370619] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 191.375630] ? recalc_sigpending_tsk+0x180/0x180 [ 191.380368] ? kasan_check_write+0x14/0x20 [ 191.384588] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 191.389416] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 191.394587] RIP: 0033:0x4572d9 [ 191.397761] 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 [ 191.416655] RSP: 002b:00007ff90ad2ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 191.424364] RAX: ffffffffffffffda RBX: 00007ff90ad2f6d4 RCX: 00000000004572d9 [ 191.431625] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 191.438878] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 191.447172] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000fff