[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.902689] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 24.491270] random: sshd: uninitialized urandom read (32 bytes read) [ 24.741683] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.275653] random: sshd: uninitialized urandom read (32 bytes read) [ 25.452568] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.14' (ECDSA) to the list of known hosts. [ 31.088970] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/02 13:21:41 parsed 1 programs [ 32.337472] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/02 13:21:43 executed programs: 0 [ 33.586859] IPVS: ftp: loaded support on port[0] = 21 [ 33.807612] bridge0: port 1(bridge_slave_0) entered blocking state [ 33.814062] bridge0: port 1(bridge_slave_0) entered disabled state [ 33.821607] device bridge_slave_0 entered promiscuous mode [ 33.838663] bridge0: port 2(bridge_slave_1) entered blocking state [ 33.845025] bridge0: port 2(bridge_slave_1) entered disabled state [ 33.852214] device bridge_slave_1 entered promiscuous mode [ 33.868618] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 33.886138] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 33.930897] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 33.951404] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 34.019760] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 34.027061] team0: Port device team_slave_0 added [ 34.042749] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 34.049923] team0: Port device team_slave_1 added [ 34.066725] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 34.086794] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 34.104911] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.123246] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.257360] bridge0: port 2(bridge_slave_1) entered blocking state [ 34.263839] bridge0: port 2(bridge_slave_1) entered forwarding state [ 34.270825] bridge0: port 1(bridge_slave_0) entered blocking state [ 34.277243] bridge0: port 1(bridge_slave_0) entered forwarding state [ 34.737424] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 34.743545] 8021q: adding VLAN 0 to HW filter on device bond0 [ 34.752691] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 34.800285] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 34.848396] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 34.854602] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 34.862419] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 34.907204] 8021q: adding VLAN 0 to HW filter on device team0 [ 35.216962] [ 35.218620] ====================================================== [ 35.224920] WARNING: possible circular locking dependency detected [ 35.231702] 4.19.0-rc1+ #218 Not tainted [ 35.235736] ------------------------------------------------------ [ 35.242050] syz-executor0/4963 is trying to acquire lock: [ 35.247576] 000000000fdab377 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 35.256876] [ 35.256876] but task is already holding lock: [ 35.262857] 0000000085ca5527 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 35.270587] [ 35.270587] which lock already depends on the new lock. [ 35.270587] [ 35.278881] [ 35.278881] the existing dependency chain (in reverse order) is: [ 35.286497] [ 35.286497] -> #2 (rtnl_mutex){+.+.}: [ 35.291794] __mutex_lock+0x171/0x1700 [ 35.296195] mutex_lock_nested+0x16/0x20 [ 35.300775] rtnl_lock+0x17/0x20 [ 35.304648] bond_netdev_notify_work+0x44/0xd0 [ 35.309737] process_one_work+0xc73/0x1aa0 [ 35.314503] worker_thread+0x189/0x13c0 [ 35.318991] kthread+0x35a/0x420 [ 35.322859] ret_from_fork+0x3a/0x50 [ 35.327070] [ 35.327070] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 35.334798] process_one_work+0xc0b/0x1aa0 [ 35.339535] worker_thread+0x189/0x13c0 [ 35.344029] kthread+0x35a/0x420 [ 35.347910] ret_from_fork+0x3a/0x50 [ 35.352122] [ 35.352122] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 35.359041] lock_acquire+0x1e4/0x4f0 [ 35.363343] flush_workqueue+0x30a/0x1e10 [ 35.367992] drain_workqueue+0x2a9/0x640 [ 35.372555] destroy_workqueue+0xc6/0x9d0 [ 35.377218] __alloc_workqueue_key+0xef9/0x1190 [ 35.382405] bond_init+0x269/0x940 [ 35.386448] register_netdevice+0x337/0x1100 [ 35.391362] bond_newlink+0x49/0xa0 [ 35.395508] rtnl_newlink+0xef4/0x1d50 [ 35.399910] rtnetlink_rcv_msg+0x46e/0xc30 [ 35.404648] netlink_rcv_skb+0x172/0x440 [ 35.409223] rtnetlink_rcv+0x1c/0x20 [ 35.413442] netlink_unicast+0x5a0/0x760 [ 35.418004] netlink_sendmsg+0xa18/0xfc0 [ 35.422570] sock_sendmsg+0xd5/0x120 [ 35.426791] ___sys_sendmsg+0x7fd/0x930 [ 35.431269] __sys_sendmsg+0x11d/0x290 [ 35.435660] __x64_sys_sendmsg+0x78/0xb0 [ 35.440233] do_syscall_64+0x1b9/0x820 [ 35.444627] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.450315] [ 35.450315] other info that might help us debug this: [ 35.450315] [ 35.458454] Chain exists of: [ 35.458454] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 35.458454] [ 35.472142] Possible unsafe locking scenario: [ 35.472142] [ 35.478186] CPU0 CPU1 [ 35.482853] ---- ---- [ 35.487517] lock(rtnl_mutex); [ 35.490779] lock((work_completion)(&(&nnw->work)->work)); [ 35.499002] lock(rtnl_mutex); [ 35.504777] lock((wq_completion)bond_dev->name); [ 35.509683] [ 35.509683] *** DEADLOCK *** [ 35.509683] [ 35.515734] 1 lock held by syz-executor0/4963: [ 35.520290] #0: 0000000085ca5527 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 35.528433] [ 35.528433] stack backtrace: [ 35.532921] CPU: 0 PID: 4963 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #218 [ 35.540197] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 35.549541] Call Trace: [ 35.552119] dump_stack+0x1c9/0x2b4 [ 35.555769] ? dump_stack_print_info.cold.2+0x52/0x52 [ 35.560954] ? vprintk_func+0x81/0x117 [ 35.564825] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 35.570517] ? save_trace+0xe0/0x290 [ 35.574217] __lock_acquire+0x3449/0x5020 [ 35.578349] ? mark_held_locks+0x160/0x160 [ 35.582570] ? mark_held_locks+0x160/0x160 [ 35.586786] ? __lock_is_held+0xb5/0x140 [ 35.590829] ? __account_cfs_rq_runtime+0x770/0x770 [ 35.595828] ? set_next_entity+0x2f0/0xa80 [ 35.600044] lock_acquire+0x1e4/0x4f0 [ 35.603828] ? flush_workqueue+0x2db/0x1e10 [ 35.608142] ? lock_release+0x9f0/0x9f0 [ 35.612104] ? lockdep_init_map+0x9/0x10 [ 35.616147] ? __init_waitqueue_head+0x9e/0x150 [ 35.620803] ? init_wait_entry+0x1c0/0x1c0 [ 35.625025] flush_workqueue+0x30a/0x1e10 [ 35.629156] ? flush_workqueue+0x2db/0x1e10 [ 35.633473] ? lock_acquire+0x1e4/0x4f0 [ 35.637431] ? drain_workqueue+0xa9/0x640 [ 35.641564] ? lock_release+0x9f0/0x9f0 [ 35.645521] ? check_same_owner+0x340/0x340 [ 35.649829] ? __queue_delayed_work+0x390/0x390 [ 35.654482] ? graph_lock+0x170/0x170 [ 35.658266] ? kasan_check_write+0x14/0x20 [ 35.662503] ? __mutex_lock+0x6d0/0x1700 [ 35.666548] ? drain_workqueue+0xa9/0x640 [ 35.670678] ? finish_task_switch+0x2ca/0x870 [ 35.675158] ? find_held_lock+0x36/0x1c0 [ 35.679216] ? lock_downgrade+0x8f0/0x8f0 [ 35.683347] ? __schedule+0x884/0x1df0 [ 35.687222] ? graph_lock+0x170/0x170 [ 35.691005] ? find_held_lock+0x36/0x1c0 [ 35.695050] ? kasan_check_write+0x14/0x20 [ 35.699272] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 35.704193] ? wait_for_completion+0x8d0/0x8d0 [ 35.708774] ? do_raw_spin_unlock+0xa7/0x2f0 [ 35.713171] ? trace_hardirqs_on+0x2c0/0x2c0 [ 35.717582] drain_workqueue+0x2a9/0x640 [ 35.721627] ? drain_workqueue+0x2a9/0x640 [ 35.725845] ? flush_workqueue+0x1e10/0x1e10 [ 35.730238] ? save_stack+0xa9/0xd0 [ 35.733845] ? save_stack+0x43/0xd0 [ 35.737455] ? __kasan_slab_free+0x11a/0x170 [ 35.741867] ? kasan_slab_free+0xe/0x10 [ 35.745829] ? print_usage_bug+0xc0/0xc0 [ 35.749873] ? bond_init+0x269/0x940 [ 35.753582] ? register_netdevice+0x337/0x1100 [ 35.758145] ? bond_newlink+0x49/0xa0 [ 35.761935] ? rtnl_newlink+0xef4/0x1d50 [ 35.765982] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 35.770372] ? netlink_rcv_skb+0x172/0x440 [ 35.774601] ? rtnetlink_rcv+0x1c/0x20 [ 35.778471] ? netlink_unicast+0x5a0/0x760 [ 35.782685] ? netlink_sendmsg+0xa18/0xfc0 [ 35.786913] ? sock_sendmsg+0xd5/0x120 [ 35.790795] destroy_workqueue+0xc6/0x9d0 [ 35.794945] ? kasan_check_write+0x14/0x20 [ 35.799169] ? wq_watchdog_timer_fn+0x830/0x830 [ 35.803834] ? mark_held_locks+0xc9/0x160 [ 35.807968] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 35.813054] ? kfree+0x111/0x210 [ 35.816404] ? kfree+0x111/0x210 [ 35.819755] ? lockdep_hardirqs_on+0x421/0x5c0 [ 35.824319] ? trace_hardirqs_on+0xbd/0x2c0 [ 35.828625] ? init_rescuer.part.26+0x155/0x190 [ 35.833276] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 35.838365] ? __kasan_slab_free+0x131/0x170 [ 35.842765] ? init_rescuer.part.26+0x155/0x190 [ 35.847424] __alloc_workqueue_key+0xef9/0x1190 [ 35.852082] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.857602] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 35.862606] ? put_dec+0xf0/0xf0 [ 35.865955] ? format_decode+0x1b1/0xaf0 [ 35.870003] ? set_precision+0xe0/0xe0 [ 35.873873] ? simple_strtoll+0xa0/0xa0 [ 35.877844] ? graph_lock+0x170/0x170 [ 35.881628] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 35.887145] ? vsnprintf+0x20d/0x1b60 [ 35.890933] ? find_held_lock+0x36/0x1c0 [ 35.894978] ? lock_downgrade+0x8f0/0x8f0 [ 35.899111] ? kasan_check_read+0x11/0x20 [ 35.903242] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 35.907910] bond_init+0x269/0x940 [ 35.911439] ? __dev_get_by_name+0x170/0x170 [ 35.915828] ? bond_arp_rcv+0x11c0/0x11c0 [ 35.919965] ? dev_valid_name+0x17b/0x2c0 [ 35.924095] ? dev_valid_name+0x197/0x2c0 [ 35.928234] ? bond_arp_rcv+0x11c0/0x11c0 [ 35.932369] register_netdevice+0x337/0x1100 [ 35.936763] ? netdev_change_features+0x110/0x110 [ 35.941592] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 35.947111] ? ns_capable_common+0x13f/0x170 [ 35.951518] ? ns_capable+0x22/0x30 [ 35.955130] bond_newlink+0x49/0xa0 [ 35.958741] ? bond_changelink+0x2360/0x2360 [ 35.963135] rtnl_newlink+0xef4/0x1d50 [ 35.967012] ? rtnl_link_unregister+0x390/0x390 [ 35.971662] ? print_usage_bug+0xc0/0xc0 [ 35.975703] ? __lock_acquire+0x7fc/0x5020 [ 35.979927] ? print_usage_bug+0xc0/0xc0 [ 35.983970] ? graph_lock+0x170/0x170 [ 35.987753] ? print_usage_bug+0xc0/0xc0 [ 35.991793] ? mark_held_locks+0x160/0x160 [ 35.996027] ? __lock_acquire+0x7fc/0x5020 [ 36.000254] ? lock_acquire+0x1e4/0x4f0 [ 36.004226] ? rtnetlink_rcv_msg+0x412/0xc30 [ 36.008621] ? lock_release+0x9f0/0x9f0 [ 36.012583] ? check_same_owner+0x340/0x340 [ 36.016925] ? mutex_trylock+0x2b0/0x2b0 [ 36.020971] ? __lock_acquire+0x7fc/0x5020 [ 36.025203] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.030731] ? refcount_sub_and_test_checked+0x21a/0x350 [ 36.036182] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.041717] ? rtnl_get_link+0x170/0x370 [ 36.045763] ? rtnl_dump_all+0x600/0x600 [ 36.049806] ? rcu_is_watching+0x8c/0x150 [ 36.053946] ? rtnl_link_unregister+0x390/0x390 [ 36.058596] rtnetlink_rcv_msg+0x46e/0xc30 [ 36.062814] ? rtnetlink_put_metrics+0x690/0x690 [ 36.067557] netlink_rcv_skb+0x172/0x440 [ 36.071601] ? rtnetlink_put_metrics+0x690/0x690 [ 36.076340] ? netlink_ack+0xbe0/0xbe0 [ 36.080218] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.084963] rtnetlink_rcv+0x1c/0x20 [ 36.088660] netlink_unicast+0x5a0/0x760 [ 36.092703] ? netlink_attachskb+0x9a0/0x9a0 [ 36.097096] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.102618] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 36.107616] netlink_sendmsg+0xa18/0xfc0 [ 36.111685] ? netlink_unicast+0x760/0x760 [ 36.115924] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 36.120839] ? apparmor_socket_sendmsg+0x29/0x30 [ 36.125579] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.131120] ? security_socket_sendmsg+0x94/0xc0 [ 36.135858] ? netlink_unicast+0x760/0x760 [ 36.140076] sock_sendmsg+0xd5/0x120 [ 36.143776] ___sys_sendmsg+0x7fd/0x930 [ 36.147733] ? copy_msghdr_from_user+0x580/0x580 [ 36.152475] ? lock_downgrade+0x8f0/0x8f0 [ 36.156611] ? __fget_light+0x2f7/0x440 [ 36.160580] ? fget_raw+0x20/0x20 [ 36.164020] ? __fd_install+0x2db/0x880 [ 36.167978] ? get_unused_fd_flags+0x1a0/0x1a0 [ 36.172548] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.178067] ? sockfd_lookup_light+0xc5/0x160 [ 36.182554] __sys_sendmsg+0x11d/0x290 [ 36.186429] ? __ia32_sys_shutdown+0x80/0x80 [ 36.190820] ? __x64_sys_futex+0x47f/0x6a0 [ 36.195042] ? do_syscall_64+0x9a/0x820 [ 36.199008] ? do_syscall_64+0x9a/0x820 [ 36.202979] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.208067] ? trace_hardirqs_off+0xb8/0x2b0 [ 36.212458] __x64_sys_sendmsg+0x78/0xb0 [ 36.216500] do_syscall_64+0x1b9/0x820 [ 36.220372] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 36.225727] ? syscall_return_slowpath+0x5e0/0x5e0 [ 36.230646] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 36.235647] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 36.240644] ? recalc_sigpending_tsk+0x180/0x180 [ 36.245386] ? kasan_check_write+0x14/0x20 [ 36.249620] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 36.254459] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 36.259633] RIP: 0033:0x457099 [ 36.262810] 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 [ 36.281693] RSP: 002b:00007f28e21acc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 36.289381] RAX: ffffffffffffffda RBX: 00007f28e21ad6d4 RCX: 0000000000457099 [ 36.296647] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 36.303923] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 36.311190] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 36.318451] R13: 00000000004d4890 R14: