[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.310116] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.604999] random: sshd: uninitialized urandom read (32 bytes read) [ 26.940282] random: sshd: uninitialized urandom read (32 bytes read) [ 27.465124] random: sshd: uninitialized urandom read (32 bytes read) [ 168.353166] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.49' (ECDSA) to the list of known hosts. [ 173.884211] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/01 13:38:09 parsed 1 programs [ 175.080577] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/01 13:38:11 executed programs: 0 [ 176.199065] IPVS: ftp: loaded support on port[0] = 21 [ 176.415274] bridge0: port 1(bridge_slave_0) entered blocking state [ 176.421980] bridge0: port 1(bridge_slave_0) entered disabled state [ 176.429859] device bridge_slave_0 entered promiscuous mode [ 176.447337] bridge0: port 2(bridge_slave_1) entered blocking state [ 176.453744] bridge0: port 2(bridge_slave_1) entered disabled state [ 176.461073] device bridge_slave_1 entered promiscuous mode [ 176.477967] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 176.495296] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 176.541512] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 176.560946] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 176.630373] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 176.637776] team0: Port device team_slave_0 added [ 176.654049] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 176.661193] team0: Port device team_slave_1 added [ 176.678297] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 176.697232] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 176.715842] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 176.735247] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 176.864212] bridge0: port 2(bridge_slave_1) entered blocking state [ 176.870681] bridge0: port 2(bridge_slave_1) entered forwarding state [ 176.877430] bridge0: port 1(bridge_slave_0) entered blocking state [ 176.883806] bridge0: port 1(bridge_slave_0) entered forwarding state [ 177.334768] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 177.340955] 8021q: adding VLAN 0 to HW filter on device bond0 [ 177.387201] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 177.406822] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 177.436690] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 177.443079] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 177.450537] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 177.498240] 8021q: adding VLAN 0 to HW filter on device team0 [ 177.787145] [ 177.788789] ====================================================== [ 177.795082] WARNING: possible circular locking dependency detected [ 177.801377] 4.19.0-rc1-next-20180831+ #53 Not tainted [ 177.806550] ------------------------------------------------------ [ 177.812848] syz-executor0/4925 is trying to acquire lock: [ 177.818364] 000000005af587ba ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 177.827649] [ 177.827649] but task is already holding lock: [ 177.833598] 0000000096fe1276 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 177.841436] [ 177.841436] which lock already depends on the new lock. [ 177.841436] [ 177.849744] [ 177.849744] the existing dependency chain (in reverse order) is: [ 177.857488] [ 177.857488] -> #2 (rtnl_mutex){+.+.}: [ 177.862770] __mutex_lock+0x171/0x1700 [ 177.867163] mutex_lock_nested+0x16/0x20 [ 177.871738] rtnl_lock+0x17/0x20 [ 177.875730] bond_netdev_notify_work+0x44/0xd0 [ 177.880820] process_one_work+0xc73/0x1aa0 [ 177.885560] worker_thread+0x189/0x13c0 [ 177.890042] kthread+0x35a/0x420 [ 177.893921] ret_from_fork+0x3a/0x50 [ 177.898131] [ 177.898131] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 177.905883] process_one_work+0xc0b/0x1aa0 [ 177.910629] worker_thread+0x189/0x13c0 [ 177.915118] kthread+0x35a/0x420 [ 177.919031] ret_from_fork+0x3a/0x50 [ 177.923246] [ 177.923246] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 177.930242] lock_acquire+0x1e4/0x4f0 [ 177.934548] flush_workqueue+0x30a/0x1e10 [ 177.939213] drain_workqueue+0x2a9/0x640 [ 177.943796] destroy_workqueue+0xc6/0x9d0 [ 177.948458] __alloc_workqueue_key+0xef9/0x1190 [ 177.953636] bond_init+0x269/0x940 [ 177.957697] register_netdevice+0x337/0x1100 [ 177.962622] bond_newlink+0x49/0xa0 [ 177.966762] rtnl_newlink+0xef4/0x1d50 [ 177.971172] rtnetlink_rcv_msg+0x46e/0xc30 [ 177.975909] netlink_rcv_skb+0x172/0x440 [ 177.980477] rtnetlink_rcv+0x1c/0x20 [ 177.984696] netlink_unicast+0x5a0/0x760 [ 177.989261] netlink_sendmsg+0xa18/0xfc0 [ 177.993829] sock_sendmsg+0xd5/0x120 [ 177.998044] ___sys_sendmsg+0x7fd/0x930 [ 178.002529] __sys_sendmsg+0x11d/0x290 [ 178.006918] __x64_sys_sendmsg+0x78/0xb0 [ 178.011496] do_syscall_64+0x1b9/0x820 [ 178.015900] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 178.021634] [ 178.021634] other info that might help us debug this: [ 178.021634] [ 178.029787] Chain exists of: [ 178.029787] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 178.029787] [ 178.043581] Possible unsafe locking scenario: [ 178.043581] [ 178.049669] CPU0 CPU1 [ 178.054333] ---- ---- [ 178.058975] lock(rtnl_mutex); [ 178.062238] lock((work_completion)(&(&nnw->work)->work)); [ 178.070494] lock(rtnl_mutex); [ 178.076340] lock((wq_completion)bond_dev->name); [ 178.081258] [ 178.081258] *** DEADLOCK *** [ 178.081258] [ 178.087304] 1 lock held by syz-executor0/4925: [ 178.091926] #0: 0000000096fe1276 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 178.100273] [ 178.100273] stack backtrace: [ 178.104762] CPU: 1 PID: 4925 Comm: syz-executor0 Not tainted 4.19.0-rc1-next-20180831+ #53 [ 178.113146] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 178.122514] Call Trace: [ 178.125091] dump_stack+0x1c9/0x2b4 [ 178.128710] ? dump_stack_print_info.cold.2+0x52/0x52 [ 178.133888] ? vprintk_func+0x81/0x117 [ 178.137764] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 178.143480] ? save_trace+0xe0/0x290 [ 178.147198] __lock_acquire+0x3449/0x5020 [ 178.151332] ? mark_held_locks+0x160/0x160 [ 178.155566] ? mark_held_locks+0x160/0x160 [ 178.159814] ? __lock_is_held+0xb5/0x140 [ 178.163859] ? __account_cfs_rq_runtime+0x770/0x770 [ 178.168896] ? set_next_entity+0x2f0/0xa80 [ 178.173116] lock_acquire+0x1e4/0x4f0 [ 178.176926] ? flush_workqueue+0x2db/0x1e10 [ 178.181234] ? lock_release+0x9f0/0x9f0 [ 178.185195] ? lockdep_init_map+0x9/0x10 [ 178.189259] ? __init_waitqueue_head+0x9e/0x150 [ 178.193929] ? init_wait_entry+0x1c0/0x1c0 [ 178.198152] flush_workqueue+0x30a/0x1e10 [ 178.202292] ? flush_workqueue+0x2db/0x1e10 [ 178.206599] ? lock_acquire+0x1e4/0x4f0 [ 178.210576] ? drain_workqueue+0xa9/0x640 [ 178.214723] ? lock_release+0x9f0/0x9f0 [ 178.218690] ? check_same_owner+0x340/0x340 [ 178.222998] ? __queue_delayed_work+0x390/0x390 [ 178.227658] ? graph_lock+0x170/0x170 [ 178.231470] ? kasan_check_write+0x14/0x20 [ 178.235797] ? __mutex_lock+0x6d0/0x1700 [ 178.239845] ? drain_workqueue+0xa9/0x640 [ 178.243977] ? finish_task_switch+0x2ca/0x870 [ 178.248457] ? find_held_lock+0x36/0x1c0 [ 178.252508] ? lock_downgrade+0x8f0/0x8f0 [ 178.256644] ? __schedule+0x884/0x1df0 [ 178.260530] ? graph_lock+0x170/0x170 [ 178.264330] ? find_held_lock+0x36/0x1c0 [ 178.268378] ? kasan_check_write+0x14/0x20 [ 178.272603] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 178.277518] ? wait_for_completion+0x8d0/0x8d0 [ 178.282087] ? do_raw_spin_unlock+0xa7/0x2f0 [ 178.286480] ? trace_hardirqs_on+0x2c0/0x2c0 [ 178.290899] drain_workqueue+0x2a9/0x640 [ 178.294972] ? drain_workqueue+0x2a9/0x640 [ 178.299193] ? flush_workqueue+0x1e10/0x1e10 [ 178.303586] ? save_stack+0xa9/0xd0 [ 178.307325] ? save_stack+0x43/0xd0 [ 178.310941] ? __kasan_slab_free+0x11a/0x170 [ 178.315334] ? kasan_slab_free+0xe/0x10 [ 178.319289] ? print_usage_bug+0xc0/0xc0 [ 178.323335] ? bond_init+0x269/0x940 [ 178.327031] ? register_netdevice+0x337/0x1100 [ 178.331595] ? bond_newlink+0x49/0xa0 [ 178.335388] ? rtnl_newlink+0xef4/0x1d50 [ 178.339453] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 178.343845] ? netlink_rcv_skb+0x172/0x440 [ 178.348086] ? rtnetlink_rcv+0x1c/0x20 [ 178.351959] ? netlink_unicast+0x5a0/0x760 [ 178.356181] ? netlink_sendmsg+0xa18/0xfc0 [ 178.360424] ? sock_sendmsg+0xd5/0x120 [ 178.364320] destroy_workqueue+0xc6/0x9d0 [ 178.368456] ? kasan_check_write+0x14/0x20 [ 178.372689] ? wq_watchdog_timer_fn+0x830/0x830 [ 178.377359] ? mark_held_locks+0xc9/0x160 [ 178.381513] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 178.386637] ? kfree+0x111/0x210 [ 178.390001] ? kfree+0x111/0x210 [ 178.393366] ? lockdep_hardirqs_on+0x421/0x5c0 [ 178.397951] ? trace_hardirqs_on+0xbd/0x2c0 [ 178.402259] ? init_rescuer.part.26+0x155/0x190 [ 178.406932] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 178.412043] ? __kasan_slab_free+0x131/0x170 [ 178.416439] ? init_rescuer.part.26+0x155/0x190 [ 178.421099] __alloc_workqueue_key+0xef9/0x1190 [ 178.425773] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 178.431322] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 178.436319] ? put_dec+0xf0/0xf0 [ 178.439676] ? format_decode+0x1b1/0xaf0 [ 178.443732] ? set_precision+0xe0/0xe0 [ 178.447603] ? simple_strtoll+0xa0/0xa0 [ 178.451576] ? graph_lock+0x170/0x170 [ 178.455385] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 178.460949] ? vsnprintf+0x20d/0x1b60 [ 178.464733] ? find_held_lock+0x36/0x1c0 [ 178.468798] ? lock_downgrade+0x8f0/0x8f0 [ 178.472933] ? kasan_check_read+0x11/0x20 [ 178.477065] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 178.481723] bond_init+0x269/0x940 [ 178.485248] ? __dev_get_by_name+0x170/0x170 [ 178.489646] ? bond_arp_rcv+0x11c0/0x11c0 [ 178.493810] ? check_same_owner+0x340/0x340 [ 178.498144] ? rcu_note_context_switch+0x680/0x680 [ 178.503078] ? bond_arp_rcv+0x11c0/0x11c0 [ 178.507211] register_netdevice+0x337/0x1100 [ 178.511604] ? netdev_change_features+0x110/0x110 [ 178.516435] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 178.521971] ? ns_capable_common+0x13f/0x170 [ 178.526387] ? ns_capable+0x22/0x30 [ 178.530025] bond_newlink+0x49/0xa0 [ 178.533661] ? bond_changelink+0x2360/0x2360 [ 178.538061] rtnl_newlink+0xef4/0x1d50 [ 178.541932] ? rtnl_link_unregister+0x390/0x390 [ 178.546587] ? print_usage_bug+0xc0/0xc0 [ 178.550630] ? __lock_acquire+0x7fc/0x5020 [ 178.554869] ? print_usage_bug+0xc0/0xc0 [ 178.558920] ? graph_lock+0x170/0x170 [ 178.562736] ? print_usage_bug+0xc0/0xc0 [ 178.566817] ? mark_held_locks+0x160/0x160 [ 178.571050] ? __lock_acquire+0x7fc/0x5020 [ 178.575292] ? lock_acquire+0x1e4/0x4f0 [ 178.579263] ? rtnetlink_rcv_msg+0x412/0xc30 [ 178.583696] ? lock_release+0x9f0/0x9f0 [ 178.587672] ? check_same_owner+0x340/0x340 [ 178.592006] ? mutex_trylock+0x2b0/0x2b0 [ 178.596064] ? __lock_acquire+0x7fc/0x5020 [ 178.600301] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 178.605842] ? refcount_sub_and_test_checked+0x21a/0x350 [ 178.611304] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 178.616851] ? rtnl_get_link+0x170/0x370 [ 178.620909] ? rtnl_dump_all+0x600/0x600 [ 178.624968] ? rcu_is_watching+0x8c/0x150 [ 178.629116] ? rtnl_link_unregister+0x390/0x390 [ 178.633786] rtnetlink_rcv_msg+0x46e/0xc30 [ 178.638023] ? rtnetlink_put_metrics+0x690/0x690 [ 178.642782] netlink_rcv_skb+0x172/0x440 [ 178.646842] ? rtnetlink_put_metrics+0x690/0x690 [ 178.651605] ? netlink_ack+0xbe0/0xbe0 [ 178.655488] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 178.660156] rtnetlink_rcv+0x1c/0x20 [ 178.663874] netlink_unicast+0x5a0/0x760 [ 178.667937] ? netlink_attachskb+0x9a0/0x9a0 [ 178.672347] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 178.677882] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 178.682900] netlink_sendmsg+0xa18/0xfc0 [ 178.686992] ? netlink_unicast+0x760/0x760 [ 178.691227] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 178.696159] ? apparmor_socket_sendmsg+0x29/0x30 [ 178.700917] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 178.706455] ? security_socket_sendmsg+0x94/0xc0 [ 178.711229] ? netlink_unicast+0x760/0x760 [ 178.715460] sock_sendmsg+0xd5/0x120 [ 178.719176] ___sys_sendmsg+0x7fd/0x930 [ 178.723150] ? copy_msghdr_from_user+0x580/0x580 [ 178.727909] ? lock_downgrade+0x8f0/0x8f0 [ 178.732056] ? __fget_light+0x2f7/0x440 [ 178.736026] ? fget_raw+0x20/0x20 [ 178.739480] ? __fd_install+0x2db/0x880 [ 178.743455] ? get_unused_fd_flags+0x1a0/0x1a0 [ 178.748042] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 178.753586] ? sockfd_lookup_light+0xc5/0x160 [ 178.758594] __sys_sendmsg+0x11d/0x290 [ 178.762480] ? __ia32_sys_shutdown+0x80/0x80 [ 178.766890] ? __x64_sys_futex+0x47f/0x6a0 [ 178.771122] ? do_syscall_64+0x9a/0x820 [ 178.775096] ? do_syscall_64+0x9a/0x820 [ 178.779090] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 178.784222] ? trace_hardirqs_off+0xb8/0x2b0 [ 178.788634] __x64_sys_sendmsg+0x78/0xb0 [ 178.792698] do_syscall_64+0x1b9/0x820 [ 178.796586] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 178.801950] ? syscall_return_slowpath+0x5e0/0x5e0 [ 178.806878] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 178.811895] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 178.816911] ? recalc_sigpending_tsk+0x180/0x180 [ 178.821666] ? kasan_check_write+0x14/0x20 [ 178.825904] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 178.830749] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 178.835936] RIP: 0033:0x457099 [ 178.839175] 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 [ 178.858075] RSP: 002b:00007f19f89cdc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 178.865810] RAX: ffffffffffffffda RBX: 00007f19f89ce6d4 RCX: 0000000000457099 [ 178.873082] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 178.880345] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 178.887626] R10: 0000000000000000 R11: 0000000000