[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 24.754014] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 28.621144] random: sshd: uninitialized urandom read (32 bytes read) [ 28.821842] random: sshd: uninitialized urandom read (32 bytes read) [ 29.366871] random: sshd: uninitialized urandom read (32 bytes read) [ 202.596214] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.53' (ECDSA) to the list of known hosts. [ 208.230189] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/02 13:20:36 parsed 1 programs [ 209.445174] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/02 13:20:38 executed programs: 0 [ 210.859695] IPVS: ftp: loaded support on port[0] = 21 [ 211.078581] bridge0: port 1(bridge_slave_0) entered blocking state [ 211.085167] bridge0: port 1(bridge_slave_0) entered disabled state [ 211.092447] device bridge_slave_0 entered promiscuous mode [ 211.110030] bridge0: port 2(bridge_slave_1) entered blocking state [ 211.116505] bridge0: port 2(bridge_slave_1) entered disabled state [ 211.123542] device bridge_slave_1 entered promiscuous mode [ 211.139557] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 211.156015] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 211.200280] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 211.218610] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 211.284994] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 211.292269] team0: Port device team_slave_0 added [ 211.307341] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 211.314474] team0: Port device team_slave_1 added [ 211.329795] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 211.347481] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 211.364212] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 211.382622] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 211.510578] bridge0: port 2(bridge_slave_1) entered blocking state [ 211.517082] bridge0: port 2(bridge_slave_1) entered forwarding state [ 211.523942] bridge0: port 1(bridge_slave_0) entered blocking state [ 211.530378] bridge0: port 1(bridge_slave_0) entered forwarding state [ 211.990942] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 211.997133] 8021q: adding VLAN 0 to HW filter on device bond0 [ 212.019731] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 212.050037] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 212.096879] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 212.103104] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 212.110450] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 212.149984] 8021q: adding VLAN 0 to HW filter on device team0 [ 212.443359] [ 212.444999] ====================================================== [ 212.451295] WARNING: possible circular locking dependency detected [ 212.457603] 4.19.0-rc1+ #198 Not tainted [ 212.461644] ------------------------------------------------------ [ 212.467935] syz-executor0/4936 is trying to acquire lock: [ 212.473448] 00000000ee395684 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 212.482719] [ 212.482719] but task is already holding lock: [ 212.488674] 00000000f4dedf94 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 212.496392] [ 212.496392] which lock already depends on the new lock. [ 212.496392] [ 212.504693] [ 212.504693] the existing dependency chain (in reverse order) is: [ 212.512291] [ 212.512291] -> #2 (rtnl_mutex){+.+.}: [ 212.517561] __mutex_lock+0x171/0x1700 [ 212.521956] mutex_lock_nested+0x16/0x20 [ 212.526520] rtnl_lock+0x17/0x20 [ 212.530387] bond_netdev_notify_work+0x44/0xd0 [ 212.535494] process_one_work+0xc73/0x1aa0 [ 212.540243] worker_thread+0x189/0x13c0 [ 212.544728] kthread+0x35a/0x420 [ 212.548598] ret_from_fork+0x3a/0x50 [ 212.552822] [ 212.552822] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 212.560527] process_one_work+0xc0b/0x1aa0 [ 212.565272] worker_thread+0x189/0x13c0 [ 212.569758] kthread+0x35a/0x420 [ 212.573621] ret_from_fork+0x3a/0x50 [ 212.577846] [ 212.577846] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 212.584824] lock_acquire+0x1e4/0x4f0 [ 212.589133] flush_workqueue+0x30a/0x1e10 [ 212.593786] drain_workqueue+0x2a9/0x640 [ 212.598626] destroy_workqueue+0xc6/0x9d0 [ 212.603276] __alloc_workqueue_key+0xef9/0x1190 [ 212.608448] bond_init+0x269/0x940 [ 212.612489] register_netdevice+0x337/0x1100 [ 212.617397] bond_newlink+0x49/0xa0 [ 212.621527] rtnl_newlink+0xef4/0x1d50 [ 212.625917] rtnetlink_rcv_msg+0x46e/0xc30 [ 212.630653] netlink_rcv_skb+0x172/0x440 [ 212.635215] rtnetlink_rcv+0x1c/0x20 [ 212.639426] netlink_unicast+0x5a0/0x760 [ 212.643984] netlink_sendmsg+0xa18/0xfc0 [ 212.648614] sock_sendmsg+0xd5/0x120 [ 212.652892] ___sys_sendmsg+0x7fd/0x930 [ 212.657375] __sys_sendmsg+0x11d/0x290 [ 212.661761] __x64_sys_sendmsg+0x78/0xb0 [ 212.666327] do_syscall_64+0x1b9/0x820 [ 212.670718] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 212.676403] [ 212.676403] other info that might help us debug this: [ 212.676403] [ 212.684522] Chain exists of: [ 212.684522] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 212.684522] [ 212.698213] Possible unsafe locking scenario: [ 212.698213] [ 212.704248] CPU0 CPU1 [ 212.708891] ---- ---- [ 212.713650] lock(rtnl_mutex); [ 212.716912] lock((work_completion)(&(&nnw->work)->work)); [ 212.725118] lock(rtnl_mutex); [ 212.730897] lock((wq_completion)bond_dev->name); [ 212.735807] [ 212.735807] *** DEADLOCK *** [ 212.735807] [ 212.741858] 1 lock held by syz-executor0/4936: [ 212.746412] #0: 00000000f4dedf94 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 212.754552] [ 212.754552] stack backtrace: [ 212.759034] CPU: 1 PID: 4936 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #198 [ 212.766287] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 212.775619] Call Trace: [ 212.778196] dump_stack+0x1c9/0x2b4 [ 212.781810] ? dump_stack_print_info.cold.2+0x52/0x52 [ 212.786988] ? vprintk_func+0x81/0x117 [ 212.790859] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 212.796546] ? save_trace+0xe0/0x290 [ 212.800285] __lock_acquire+0x3449/0x5020 [ 212.804420] ? mark_held_locks+0x160/0x160 [ 212.808644] ? print_usage_bug+0xc0/0xc0 [ 212.812683] ? mark_held_locks+0x160/0x160 [ 212.816903] ? __lock_is_held+0xb5/0x140 [ 212.820949] ? mark_held_locks+0xc9/0x160 [ 212.825089] ? lockdep_hardirqs_on+0x421/0x5c0 [ 212.829651] lock_acquire+0x1e4/0x4f0 [ 212.833437] ? flush_workqueue+0x2db/0x1e10 [ 212.837762] ? lock_release+0x9f0/0x9f0 [ 212.843110] ? lockdep_init_map+0x9/0x10 [ 212.847165] ? __init_waitqueue_head+0x9e/0x150 [ 212.851823] ? init_wait_entry+0x1c0/0x1c0 [ 212.856048] ? retint_kernel+0x10/0x10 [ 212.859973] flush_workqueue+0x30a/0x1e10 [ 212.864113] ? flush_workqueue+0x2db/0x1e10 [ 212.868421] ? lock_release+0x9f0/0x9f0 [ 212.872377] ? check_same_owner+0x340/0x340 [ 212.876682] ? __queue_delayed_work+0x390/0x390 [ 212.881345] ? graph_lock+0x170/0x170 [ 212.885126] ? kasan_check_write+0x14/0x20 [ 212.889341] ? __mutex_lock+0x6d0/0x1700 [ 212.893488] ? drain_workqueue+0xa9/0x640 [ 212.897618] ? finish_task_switch+0x2ca/0x870 [ 212.902111] ? find_held_lock+0x36/0x1c0 [ 212.906572] ? lock_downgrade+0x8f0/0x8f0 [ 212.910704] ? __schedule+0x884/0x1df0 [ 212.914571] ? graph_lock+0x170/0x170 [ 212.918361] ? find_held_lock+0x36/0x1c0 [ 212.922408] ? kasan_check_write+0x14/0x20 [ 212.926629] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 212.931555] ? wait_for_completion+0x8d0/0x8d0 [ 212.936123] ? do_raw_spin_unlock+0xa7/0x2f0 [ 212.940521] ? trace_hardirqs_on+0x2c0/0x2c0 [ 212.944914] drain_workqueue+0x2a9/0x640 [ 212.948955] ? drain_workqueue+0x2a9/0x640 [ 212.953171] ? flush_workqueue+0x1e10/0x1e10 [ 212.957561] ? save_stack+0xa9/0xd0 [ 212.961167] ? save_stack+0x43/0xd0 [ 212.964771] ? __kasan_slab_free+0x11a/0x170 [ 212.969159] ? kasan_slab_free+0xe/0x10 [ 212.973112] ? print_usage_bug+0xc0/0xc0 [ 212.977150] ? bond_init+0x269/0x940 [ 212.980964] ? register_netdevice+0x337/0x1100 [ 212.985532] ? bond_newlink+0x49/0xa0 [ 212.989324] ? rtnl_newlink+0xef4/0x1d50 [ 212.993379] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 212.997777] ? netlink_rcv_skb+0x172/0x440 [ 213.002001] ? rtnetlink_rcv+0x1c/0x20 [ 213.005869] ? netlink_unicast+0x5a0/0x760 [ 213.010089] ? netlink_sendmsg+0xa18/0xfc0 [ 213.014315] ? sock_sendmsg+0xd5/0x120 [ 213.018204] destroy_workqueue+0xc6/0x9d0 [ 213.022358] ? kasan_check_write+0x14/0x20 [ 213.026624] ? wq_watchdog_timer_fn+0x830/0x830 [ 213.031281] ? mark_held_locks+0xc9/0x160 [ 213.035422] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 213.040510] ? kfree+0x111/0x210 [ 213.043859] ? kfree+0x111/0x210 [ 213.047214] ? lockdep_hardirqs_on+0x421/0x5c0 [ 213.051778] ? trace_hardirqs_on+0xbd/0x2c0 [ 213.056098] ? init_rescuer.part.26+0x155/0x190 [ 213.060752] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 213.065841] ? __kasan_slab_free+0x131/0x170 [ 213.070233] ? init_rescuer.part.26+0x155/0x190 [ 213.074887] __alloc_workqueue_key+0xef9/0x1190 [ 213.079551] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 213.085078] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 213.090085] ? put_dec+0xf0/0xf0 [ 213.093434] ? format_decode+0x1b1/0xaf0 [ 213.097479] ? set_precision+0xe0/0xe0 [ 213.101351] ? simple_strtoll+0xa0/0xa0 [ 213.105320] ? graph_lock+0x170/0x170 [ 213.109130] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 213.114676] ? vsnprintf+0x20d/0x1b60 [ 213.118464] ? find_held_lock+0x36/0x1c0 [ 213.122512] ? lock_downgrade+0x8f0/0x8f0 [ 213.126646] ? kasan_check_read+0x11/0x20 [ 213.130779] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 213.135440] bond_init+0x269/0x940 [ 213.138983] ? __dev_get_by_name+0x170/0x170 [ 213.143385] ? bond_arp_rcv+0x11c0/0x11c0 [ 213.147519] ? check_same_owner+0x340/0x340 [ 213.151831] ? rcu_note_context_switch+0x680/0x680 [ 213.156745] ? bond_arp_rcv+0x11c0/0x11c0 [ 213.160876] register_netdevice+0x337/0x1100 [ 213.165287] ? netdev_change_features+0x110/0x110 [ 213.170145] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 213.175680] ? ns_capable_common+0x13f/0x170 [ 213.180087] ? ns_capable+0x22/0x30 [ 213.183699] bond_newlink+0x49/0xa0 [ 213.187315] ? bond_changelink+0x2360/0x2360 [ 213.191721] rtnl_newlink+0xef4/0x1d50 [ 213.195609] ? rtnl_link_unregister+0x390/0x390 [ 213.200281] ? print_usage_bug+0xc0/0xc0 [ 213.204371] ? print_usage_bug+0xc0/0xc0 [ 213.208420] ? graph_lock+0x170/0x170 [ 213.212206] ? print_usage_bug+0xc0/0xc0 [ 213.216273] ? __lock_acquire+0x7fc/0x5020 [ 213.220521] ? lock_acquire+0x1e4/0x4f0 [ 213.224483] ? rtnetlink_rcv_msg+0x412/0xc30 [ 213.228876] ? lock_release+0x9f0/0x9f0 [ 213.232848] ? check_same_owner+0x340/0x340 [ 213.237161] ? mutex_trylock+0x2b0/0x2b0 [ 213.241227] ? __lock_acquire+0x7fc/0x5020 [ 213.245449] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 213.250988] ? refcount_sub_and_test_checked+0x21a/0x350 [ 213.256436] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 213.261964] ? rtnl_get_link+0x170/0x370 [ 213.266013] ? rtnl_dump_all+0x600/0x600 [ 213.270061] ? rcu_is_watching+0x8c/0x150 [ 213.274202] ? rtnl_link_unregister+0x390/0x390 [ 213.278868] rtnetlink_rcv_msg+0x46e/0xc30 [ 213.283101] ? rtnetlink_put_metrics+0x690/0x690 [ 213.287843] netlink_rcv_skb+0x172/0x440 [ 213.291890] ? rtnetlink_put_metrics+0x690/0x690 [ 213.296629] ? netlink_ack+0xbe0/0xbe0 [ 213.300503] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 213.305173] rtnetlink_rcv+0x1c/0x20 [ 213.308872] netlink_unicast+0x5a0/0x760 [ 213.312919] ? netlink_attachskb+0x9a0/0x9a0 [ 213.317322] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 213.322856] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 213.327858] netlink_sendmsg+0xa18/0xfc0 [ 213.331932] ? netlink_unicast+0x760/0x760 [ 213.336197] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 213.341128] ? apparmor_socket_sendmsg+0x29/0x30 [ 213.345870] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 213.351396] ? security_socket_sendmsg+0x94/0xc0 [ 213.356155] ? netlink_unicast+0x760/0x760 [ 213.360410] sock_sendmsg+0xd5/0x120 [ 213.364124] ___sys_sendmsg+0x7fd/0x930 [ 213.368084] ? copy_msghdr_from_user+0x580/0x580 [ 213.372830] ? lock_downgrade+0x8f0/0x8f0 [ 213.376963] ? __fget_light+0x2f7/0x440 [ 213.380928] ? fget_raw+0x20/0x20 [ 213.384380] ? __fd_install+0x2db/0x880 [ 213.388353] ? get_unused_fd_flags+0x1a0/0x1a0 [ 213.392931] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 213.398454] ? sockfd_lookup_light+0xc5/0x160 [ 213.402934] __sys_sendmsg+0x11d/0x290 [ 213.406815] ? __ia32_sys_shutdown+0x80/0x80 [ 213.411219] ? __x64_sys_futex+0x47f/0x6a0 [ 213.415440] ? do_syscall_64+0x9a/0x820 [ 213.419400] ? do_syscall_64+0x9a/0x820 [ 213.423374] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 213.428468] ? trace_hardirqs_off+0xb8/0x2b0 [ 213.432876] __x64_sys_sendmsg+0x78/0xb0 [ 213.436933] do_syscall_64+0x1b9/0x820 [ 213.440813] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 213.446161] ? syscall_return_slowpath+0x5e0/0x5e0 [ 213.451077] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 213.456093] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 213.461106] ? recalc_sigpending_tsk+0x180/0x180 [ 213.465864] ? kasan_check_write+0x14/0x20 [ 213.470087] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 213.474919] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 213.480111] RIP: 0033:0x457099 [ 213.483294] 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 0