[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 23.632729] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 24.802905] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 25.239243] random: sshd: uninitialized urandom read (32 bytes read) [ 25.788322] random: sshd: uninitialized urandom read (32 bytes read) [ 26.005063] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.8' (ECDSA) to the list of known hosts. [ 31.554612] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/26 19:31:29 parsed 1 programs [ 32.915151] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/26 19:31:31 executed programs: 0 [ 34.217792] IPVS: ftp: loaded support on port[0] = 21 [ 34.439766] bridge0: port 1(bridge_slave_0) entered blocking state [ 34.446272] bridge0: port 1(bridge_slave_0) entered disabled state [ 34.454167] device bridge_slave_0 entered promiscuous mode [ 34.471701] bridge0: port 2(bridge_slave_1) entered blocking state [ 34.478076] bridge0: port 2(bridge_slave_1) entered disabled state [ 34.485507] device bridge_slave_1 entered promiscuous mode [ 34.501799] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 34.518750] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 34.564948] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 34.584677] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 34.654503] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 34.662119] team0: Port device team_slave_0 added [ 34.677747] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 34.685480] team0: Port device team_slave_1 added [ 34.702526] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 34.720825] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 34.739576] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 34.758109] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 34.855171] ip (4555) used greatest stack depth: 16824 bytes left [ 34.898332] bridge0: port 2(bridge_slave_1) entered blocking state [ 34.904997] bridge0: port 2(bridge_slave_1) entered forwarding state [ 34.912146] bridge0: port 1(bridge_slave_0) entered blocking state [ 34.918541] bridge0: port 1(bridge_slave_0) entered forwarding state [ 35.390989] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 35.397109] 8021q: adding VLAN 0 to HW filter on device bond0 [ 35.411569] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 35.453018] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 35.499685] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 35.506325] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 35.513582] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 35.555330] 8021q: adding VLAN 0 to HW filter on device team0 [ 35.856033] [ 35.857869] ====================================================== [ 35.864340] WARNING: possible circular locking dependency detected [ 35.870716] 4.18.0+ #209 Not tainted [ 35.874419] ------------------------------------------------------ [ 35.880728] syz-executor0/4727 is trying to acquire lock: [ 35.886287] 000000005a8e676e ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 35.895567] [ 35.895567] but task is already holding lock: [ 35.901617] 000000007459a081 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 35.909351] [ 35.909351] which lock already depends on the new lock. [ 35.909351] [ 35.917664] [ 35.917664] the existing dependency chain (in reverse order) is: [ 35.925304] [ 35.925304] -> #2 (rtnl_mutex){+.+.}: [ 35.930598] __mutex_lock+0x171/0x1700 [ 35.935013] mutex_lock_nested+0x16/0x20 [ 35.939611] rtnl_lock+0x17/0x20 [ 35.943497] bond_netdev_notify_work+0x44/0xd0 [ 35.948761] process_one_work+0xc73/0x1aa0 [ 35.953523] worker_thread+0x189/0x13c0 [ 35.958144] kthread+0x35a/0x420 [ 35.962102] ret_from_fork+0x3a/0x50 [ 35.966389] [ 35.966389] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 35.974110] process_one_work+0xc0b/0x1aa0 [ 35.978873] worker_thread+0x189/0x13c0 [ 35.983372] kthread+0x35a/0x420 [ 35.987293] ret_from_fork+0x3a/0x50 [ 35.991519] [ 35.991519] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 35.998473] lock_acquire+0x1e4/0x4f0 [ 36.002799] flush_workqueue+0x30a/0x1e10 [ 36.007473] drain_workqueue+0x2a9/0x640 [ 36.012051] destroy_workqueue+0xc6/0x9d0 [ 36.016719] __alloc_workqueue_key+0xef9/0x1190 [ 36.022144] bond_init+0x269/0x940 [ 36.026359] register_netdevice+0x337/0x1100 [ 36.031308] bond_newlink+0x49/0xa0 [ 36.035453] rtnl_newlink+0xef4/0x1d50 [ 36.039861] rtnetlink_rcv_msg+0x46e/0xc30 [ 36.044629] netlink_rcv_skb+0x172/0x440 [ 36.049208] rtnetlink_rcv+0x1c/0x20 [ 36.053438] netlink_unicast+0x5a0/0x760 [ 36.058043] netlink_sendmsg+0xa18/0xfc0 [ 36.062695] sock_sendmsg+0xd5/0x120 [ 36.066945] ___sys_sendmsg+0x7fd/0x930 [ 36.071584] __sys_sendmsg+0x11d/0x290 [ 36.076064] __x64_sys_sendmsg+0x78/0xb0 [ 36.080643] do_syscall_64+0x1b9/0x820 [ 36.085048] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 36.090837] [ 36.090837] other info that might help us debug this: [ 36.090837] [ 36.099053] Chain exists of: [ 36.099053] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 36.099053] [ 36.112930] Possible unsafe locking scenario: [ 36.112930] [ 36.118995] CPU0 CPU1 [ 36.123657] ---- ---- [ 36.128455] lock(rtnl_mutex); [ 36.131728] lock((work_completion)(&(&nnw->work)->work)); [ 36.140045] lock(rtnl_mutex); [ 36.145836] lock((wq_completion)bond_dev->name); [ 36.150771] [ 36.150771] *** DEADLOCK *** [ 36.150771] [ 36.157021] 1 lock held by syz-executor0/4727: [ 36.161591] #0: 000000007459a081 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 36.169741] [ 36.169741] stack backtrace: [ 36.174243] CPU: 0 PID: 4727 Comm: syz-executor0 Not tainted 4.18.0+ #209 [ 36.181202] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.190701] Call Trace: [ 36.193312] dump_stack+0x1c9/0x2b4 [ 36.196946] ? dump_stack_print_info.cold.2+0x52/0x52 [ 36.202376] ? vprintk_func+0x81/0x117 [ 36.206294] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 36.212098] ? save_trace+0xe0/0x290 [ 36.215809] __lock_acquire+0x3449/0x5020 [ 36.220069] ? mark_held_locks+0x160/0x160 [ 36.224331] ? mark_held_locks+0x160/0x160 [ 36.228570] ? __lock_is_held+0xb5/0x140 [ 36.232702] ? __account_cfs_rq_runtime+0x770/0x770 [ 36.237719] ? set_next_entity+0x2f0/0xa80 [ 36.241954] lock_acquire+0x1e4/0x4f0 [ 36.245753] ? flush_workqueue+0x2db/0x1e10 [ 36.250079] ? lock_release+0x9f0/0x9f0 [ 36.254059] ? lockdep_init_map+0x9/0x10 [ 36.258116] ? __init_waitqueue_head+0x9e/0x150 [ 36.262783] ? init_wait_entry+0x1c0/0x1c0 [ 36.267018] flush_workqueue+0x30a/0x1e10 [ 36.271162] ? flush_workqueue+0x2db/0x1e10 [ 36.275477] ? lock_acquire+0x1e4/0x4f0 [ 36.279453] ? drain_workqueue+0xa9/0x640 [ 36.283660] ? lock_release+0x9f0/0x9f0 [ 36.287722] ? check_same_owner+0x340/0x340 [ 36.292042] ? __queue_delayed_work+0x390/0x390 [ 36.296767] ? graph_lock+0x170/0x170 [ 36.300568] ? kasan_check_write+0x14/0x20 [ 36.304800] ? __mutex_lock+0x6d0/0x1700 [ 36.308864] ? drain_workqueue+0xa9/0x640 [ 36.313019] ? finish_task_switch+0x2ca/0x870 [ 36.317513] ? find_held_lock+0x36/0x1c0 [ 36.321746] ? lock_downgrade+0x8f0/0x8f0 [ 36.325900] ? __schedule+0x884/0x1df0 [ 36.329799] ? graph_lock+0x170/0x170 [ 36.333602] ? find_held_lock+0x36/0x1c0 [ 36.337735] ? kasan_check_write+0x14/0x20 [ 36.341969] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 36.346908] ? wait_for_completion+0x8d0/0x8d0 [ 36.351604] ? do_raw_spin_unlock+0xa7/0x2f0 [ 36.356029] ? trace_hardirqs_on+0x2c0/0x2c0 [ 36.360514] drain_workqueue+0x2a9/0x640 [ 36.364585] ? drain_workqueue+0x2a9/0x640 [ 36.369173] ? flush_workqueue+0x1e10/0x1e10 [ 36.373579] ? save_stack+0xa9/0xd0 [ 36.377200] ? save_stack+0x43/0xd0 [ 36.380822] ? __kasan_slab_free+0x11a/0x170 [ 36.385229] ? kasan_slab_free+0xe/0x10 [ 36.389239] ? print_usage_bug+0xc0/0xc0 [ 36.393342] ? bond_init+0x269/0x940 [ 36.397069] ? register_netdevice+0x337/0x1100 [ 36.401647] ? bond_newlink+0x49/0xa0 [ 36.405447] ? rtnl_newlink+0xef4/0x1d50 [ 36.409505] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 36.413918] ? netlink_rcv_skb+0x172/0x440 [ 36.418174] ? rtnetlink_rcv+0x1c/0x20 [ 36.422312] ? netlink_unicast+0x5a0/0x760 [ 36.426540] ? netlink_sendmsg+0xa18/0xfc0 [ 36.430772] ? sock_sendmsg+0xd5/0x120 [ 36.434665] destroy_workqueue+0xc6/0x9d0 [ 36.438814] ? kasan_check_write+0x14/0x20 [ 36.443047] ? wq_watchdog_timer_fn+0x830/0x830 [ 36.447712] ? mark_held_locks+0xc9/0x160 [ 36.451862] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 36.457106] ? kfree+0x111/0x210 [ 36.460466] ? kfree+0x111/0x210 [ 36.463828] ? lockdep_hardirqs_on+0x421/0x5c0 [ 36.468408] ? trace_hardirqs_on+0xbd/0x2c0 [ 36.472726] ? init_rescuer.part.26+0x155/0x190 [ 36.477501] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.482599] ? __kasan_slab_free+0x131/0x170 [ 36.487004] ? init_rescuer.part.26+0x155/0x190 [ 36.491672] __alloc_workqueue_key+0xef9/0x1190 [ 36.496341] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.501885] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 36.506919] ? put_dec+0xf0/0xf0 [ 36.510372] ? format_decode+0x1b1/0xaf0 [ 36.514516] ? set_precision+0xe0/0xe0 [ 36.518566] ? simple_strtoll+0xa0/0xa0 [ 36.522546] ? graph_lock+0x170/0x170 [ 36.526346] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.531890] ? vsnprintf+0x20d/0x1b60 [ 36.535698] ? find_held_lock+0x36/0x1c0 [ 36.539755] ? lock_downgrade+0x8f0/0x8f0 [ 36.543989] ? kasan_check_read+0x11/0x20 [ 36.548134] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.552872] bond_init+0x269/0x940 [ 36.556423] ? __dev_get_by_name+0x170/0x170 [ 36.560824] ? bond_arp_rcv+0x11c0/0x11c0 [ 36.564972] ? check_same_owner+0x340/0x340 [ 36.569601] ? rcu_note_context_switch+0x680/0x680 [ 36.574526] ? bond_arp_rcv+0x11c0/0x11c0 [ 36.578674] register_netdevice+0x337/0x1100 [ 36.583078] ? netdev_change_features+0x110/0x110 [ 36.587929] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.593615] ? ns_capable_common+0x13f/0x170 [ 36.598024] bond_newlink+0x49/0xa0 [ 36.601645] ? bond_changelink+0x2360/0x2360 [ 36.606110] rtnl_newlink+0xef4/0x1d50 [ 36.610000] ? rtnl_link_unregister+0x390/0x390 [ 36.614666] ? print_usage_bug+0xc0/0xc0 [ 36.618726] ? mark_held_locks+0xc9/0x160 [ 36.622878] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 36.627635] ? lockdep_hardirqs_on+0x421/0x5c0 [ 36.632209] ? retint_kernel+0x10/0x10 [ 36.636086] ? trace_hardirqs_on_caller+0xc0/0x2b0 [ 36.641004] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 36.645753] ? __bpf_trace_preemptirq_template+0x30/0x30 [ 36.651194] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 36.655940] ? retint_kernel+0x10/0x10 [ 36.659822] ? mutex_trylock+0x2b0/0x2b0 [ 36.663880] ? __lock_acquire+0x7fc/0x5020 [ 36.668111] ? graph_lock+0x170/0x170 [ 36.671919] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.677446] ? rtnl_get_link+0x170/0x370 [ 36.681489] ? rtnl_dump_all+0x600/0x600 [ 36.685533] ? rcu_is_watching+0x8c/0x150 [ 36.689664] ? rtnl_link_unregister+0x390/0x390 [ 36.694315] rtnetlink_rcv_msg+0x46e/0xc30 [ 36.698531] ? rtnetlink_put_metrics+0x690/0x690 [ 36.703275] netlink_rcv_skb+0x172/0x440 [ 36.707326] ? rtnetlink_put_metrics+0x690/0x690 [ 36.712070] ? netlink_ack+0xbe0/0xbe0 [ 36.715937] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 36.720590] rtnetlink_rcv+0x1c/0x20 [ 36.724292] netlink_unicast+0x5a0/0x760 [ 36.728336] ? netlink_attachskb+0x9a0/0x9a0 [ 36.734725] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 36.740253] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 36.745257] netlink_sendmsg+0xa18/0xfc0 [ 36.749307] ? netlink_unicast+0x760/0x760 [ 36.753553] ? move_addr_to_kernel.part.18+0x100/0x100 [ 36.758811] ? security_socket_sendmsg+0x94/0xc0 [ 36.763546] ? netlink_unicast+0x760/0x760 [ 36.767762] sock_sendmsg+0xd5/0x120 [ 36.771477] ___sys_sendmsg+0x7fd/0x930 [ 36.775438] ? copy_msghdr_from_user+0x580/0x580 [ 36.780175] ? lock_downgrade+0x8f0/0x8f0 [ 36.784307] ? __fget_light+0x2f7/0x440 [ 36.788269] ? fget_raw+0x20/0x20 [ 36.791706] ? __fd_install+0x2db/0x880 [ 36.795661] ? get_unused_fd_flags+0x1a0/0x1a0 [ 36.800226] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 36.805749] ? sockfd_lookup_light+0xc5/0x160 [ 36.810227] __sys_sendmsg+0x11d/0x290 [ 36.814103] ? __ia32_sys_shutdown+0x80/0x80 [ 36.818492] ? __x64_sys_futex+0x47f/0x6a0 [ 36.822709] ? do_syscall_64+0x9a/0x820 [ 36.826666] ? do_syscall_64+0x9a/0x820 [ 36.830622] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 36.835740] ? trace_hardirqs_off+0xb8/0x2b0 [ 36.840127] __x64_sys_sendmsg+0x78/0xb0 [ 36.844168] do_syscall_64+0x1b9/0x820 [ 36.848038] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 36.853381] ? syscall_return_slowpath+0x5e0/0x5e0 [ 36.858293] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 36.863293] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 36.868296] ? recalc_sigpending_tsk+0x180/0x180 [ 36.873052] ? kasan_check_write+0x14/0x20 [ 36.877273] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 36.882104] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 36.887297] RIP: 0033:0x457089 [ 36.890472] 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 [ 36.909352] RSP: 002b:00007fecc805ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 36.917037] RAX: ffffffffffffffda RBX: 00007fecc805f6d4 RCX: 0000000000457089 [ 36.924289] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 36.931536] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 36.938784] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 36.946032] R13: 00000000004d4188 R14: 00000000004c8b53 R15: 0000000000000000 2018/08/26 19:31:36 executed programs: 130 2018/08/26 19:31:41 executed programs: 411