[....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.583770] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 23.064774] random: sshd: uninitialized urandom read (32 bytes read) [ 23.308634] random: sshd: uninitialized urandom read (32 bytes read) [ 23.841408] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.38' (ECDSA) to the list of known hosts. [ 29.514265] urandom_read: 1 callbacks suppressed [ 29.514270] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/04 10:00:46 parsed 1 programs [ 30.914291] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/04 10:00:48 executed programs: 0 [ 32.053666] IPVS: ftp: loaded support on port[0] = 21 [ 32.264084] bridge0: port 1(bridge_slave_0) entered blocking state [ 32.270555] bridge0: port 1(bridge_slave_0) entered disabled state [ 32.278028] device bridge_slave_0 entered promiscuous mode [ 32.295307] bridge0: port 2(bridge_slave_1) entered blocking state [ 32.301702] bridge0: port 2(bridge_slave_1) entered disabled state [ 32.308978] device bridge_slave_1 entered promiscuous mode [ 32.325937] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 32.343285] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 32.388512] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 32.407836] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 32.475363] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 32.482648] team0: Port device team_slave_0 added [ 32.498421] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 32.505528] team0: Port device team_slave_1 added [ 32.521462] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 32.539690] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 32.557037] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 32.576820] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 32.712533] bridge0: port 2(bridge_slave_1) entered blocking state [ 32.718966] bridge0: port 2(bridge_slave_1) entered forwarding state [ 32.725901] bridge0: port 1(bridge_slave_0) entered blocking state [ 32.732273] bridge0: port 1(bridge_slave_0) entered forwarding state [ 33.181005] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 33.187234] 8021q: adding VLAN 0 to HW filter on device bond0 [ 33.233553] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 33.262069] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 33.282756] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 33.289208] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 33.296338] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 33.337817] 8021q: adding VLAN 0 to HW filter on device team0 [ 33.626060] [ 33.627722] ====================================================== [ 33.634055] WARNING: possible circular locking dependency detected [ 33.640367] 4.19.0-rc2+ #220 Not tainted [ 33.644402] ------------------------------------------------------ [ 33.650697] syz-executor0/4837 is trying to acquire lock: [ 33.656209] 00000000f3b95024 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 33.665489] [ 33.665489] but task is already holding lock: [ 33.671436] 0000000067a8efba (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 33.679140] [ 33.679140] which lock already depends on the new lock. [ 33.679140] [ 33.687436] [ 33.687436] the existing dependency chain (in reverse order) is: [ 33.695034] [ 33.695034] -> #2 (rtnl_mutex){+.+.}: [ 33.700329] __mutex_lock+0x171/0x1700 [ 33.704721] mutex_lock_nested+0x16/0x20 [ 33.709314] rtnl_lock+0x17/0x20 [ 33.713190] bond_netdev_notify_work+0x44/0xd0 [ 33.718279] process_one_work+0xc73/0x1aa0 [ 33.723013] worker_thread+0x189/0x13c0 [ 33.727488] kthread+0x35a/0x420 [ 33.731356] ret_from_fork+0x3a/0x50 [ 33.735583] [ 33.735583] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 33.743285] process_one_work+0xc0b/0x1aa0 [ 33.748019] worker_thread+0x189/0x13c0 [ 33.752492] kthread+0x35a/0x420 [ 33.756357] ret_from_fork+0x3a/0x50 [ 33.760566] [ 33.760566] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 33.767483] lock_acquire+0x1e4/0x4f0 [ 33.771787] flush_workqueue+0x30a/0x1e10 [ 33.776433] drain_workqueue+0x2a9/0x640 [ 33.780996] destroy_workqueue+0xc6/0x9d0 [ 33.785645] __alloc_workqueue_key+0xef9/0x1190 [ 33.790837] bond_init+0x269/0x940 [ 33.794882] register_netdevice+0x337/0x1100 [ 33.799799] bond_newlink+0x49/0xa0 [ 33.803932] rtnl_newlink+0xef4/0x1d50 [ 33.808319] rtnetlink_rcv_msg+0x46e/0xc30 [ 33.813051] netlink_rcv_skb+0x172/0x440 [ 33.817611] rtnetlink_rcv+0x1c/0x20 [ 33.821826] netlink_unicast+0x5a0/0x760 [ 33.826387] netlink_sendmsg+0xa18/0xfc0 [ 33.830946] sock_sendmsg+0xd5/0x120 [ 33.835158] ___sys_sendmsg+0x7fd/0x930 [ 33.839633] __sys_sendmsg+0x11d/0x290 [ 33.844028] __x64_sys_sendmsg+0x78/0xb0 [ 33.848589] do_syscall_64+0x1b9/0x820 [ 33.852977] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 33.858669] [ 33.858669] other info that might help us debug this: [ 33.858669] [ 33.866804] Chain exists of: [ 33.866804] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 33.866804] [ 33.880498] Possible unsafe locking scenario: [ 33.880498] [ 33.886542] CPU0 CPU1 [ 33.891189] ---- ---- [ 33.895827] lock(rtnl_mutex); [ 33.899086] lock((work_completion)(&(&nnw->work)->work)); [ 33.907305] lock(rtnl_mutex); [ 33.913081] lock((wq_completion)bond_dev->name); [ 33.918002] [ 33.918002] *** DEADLOCK *** [ 33.918002] [ 33.924045] 1 lock held by syz-executor0/4837: [ 33.928604] #0: 0000000067a8efba (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 33.936754] [ 33.936754] stack backtrace: [ 33.941235] CPU: 1 PID: 4837 Comm: syz-executor0 Not tainted 4.19.0-rc2+ #220 [ 33.948484] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.957816] Call Trace: [ 33.960391] dump_stack+0x1c9/0x2b4 [ 33.964003] ? dump_stack_print_info.cold.2+0x52/0x52 [ 33.969180] ? vprintk_func+0x81/0x117 [ 33.973049] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 33.978740] ? save_trace+0xe0/0x290 [ 33.982435] __lock_acquire+0x3449/0x5020 [ 33.986569] ? mark_held_locks+0x160/0x160 [ 33.990809] ? __lock_is_held+0xb5/0x140 [ 33.994853] ? update_curr+0x344/0xba0 [ 33.998722] ? __account_cfs_rq_runtime+0x770/0x770 [ 34.003719] ? lock_downgrade+0x8f0/0x8f0 [ 34.007866] lock_acquire+0x1e4/0x4f0 [ 34.011650] ? flush_workqueue+0x2db/0x1e10 [ 34.015987] ? lock_release+0x9f0/0x9f0 [ 34.019945] ? lockdep_init_map+0x9/0x10 [ 34.024001] ? __init_waitqueue_head+0x9e/0x150 [ 34.028649] ? init_wait_entry+0x1c0/0x1c0 [ 34.032875] flush_workqueue+0x30a/0x1e10 [ 34.037002] ? flush_workqueue+0x2db/0x1e10 [ 34.041304] ? lock_acquire+0x1e4/0x4f0 [ 34.045263] ? drain_workqueue+0xa9/0x640 [ 34.049396] ? lock_release+0x9f0/0x9f0 [ 34.053349] ? check_same_owner+0x340/0x340 [ 34.057649] ? task_numa_migrate+0x28e0/0x28e0 [ 34.062509] ? __queue_delayed_work+0x390/0x390 [ 34.067156] ? graph_lock+0x170/0x170 [ 34.070941] ? kasan_check_write+0x14/0x20 [ 34.075156] ? __mutex_lock+0x6d0/0x1700 [ 34.079204] ? drain_workqueue+0xa9/0x640 [ 34.083329] ? graph_lock+0x170/0x170 [ 34.087117] ? print_usage_bug+0xc0/0xc0 [ 34.091337] ? find_held_lock+0x36/0x1c0 [ 34.095378] ? lock_downgrade+0x8f0/0x8f0 [ 34.099518] ? graph_lock+0x170/0x170 [ 34.103299] ? graph_lock+0x170/0x170 [ 34.107076] ? find_held_lock+0x36/0x1c0 [ 34.111134] ? kasan_check_write+0x14/0x20 [ 34.115354] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 34.120267] ? wait_for_completion+0x8d0/0x8d0 [ 34.124835] ? do_raw_spin_unlock+0xa7/0x2f0 [ 34.129240] ? trace_hardirqs_on+0x2c0/0x2c0 [ 34.133637] drain_workqueue+0x2a9/0x640 [ 34.137689] ? drain_workqueue+0x2a9/0x640 [ 34.141905] ? flush_workqueue+0x1e10/0x1e10 [ 34.146294] ? save_stack+0xa9/0xd0 [ 34.149900] ? save_stack+0x43/0xd0 [ 34.153609] ? __kasan_slab_free+0x11a/0x170 [ 34.157998] ? kasan_slab_free+0xe/0x10 [ 34.161974] ? print_usage_bug+0xc0/0xc0 [ 34.166029] ? bond_init+0x269/0x940 [ 34.169740] ? register_netdevice+0x337/0x1100 [ 34.174301] ? bond_newlink+0x49/0xa0 [ 34.178081] ? rtnl_newlink+0xef4/0x1d50 [ 34.182133] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 34.186522] ? netlink_rcv_skb+0x172/0x440 [ 34.190737] ? rtnetlink_rcv+0x1c/0x20 [ 34.194605] ? netlink_unicast+0x5a0/0x760 [ 34.199367] ? netlink_sendmsg+0xa18/0xfc0 [ 34.203584] ? sock_sendmsg+0xd5/0x120 [ 34.207456] destroy_workqueue+0xc6/0x9d0 [ 34.211588] ? kasan_check_write+0x14/0x20 [ 34.215807] ? wq_watchdog_timer_fn+0x830/0x830 [ 34.220457] ? mark_held_locks+0xc9/0x160 [ 34.224586] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 34.229676] ? kfree+0x111/0x210 [ 34.233024] ? kfree+0x111/0x210 [ 34.236376] ? lockdep_hardirqs_on+0x421/0x5c0 [ 34.240949] ? trace_hardirqs_on+0xbd/0x2c0 [ 34.245251] ? init_rescuer.part.26+0x155/0x190 [ 34.249901] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 34.254996] ? __kasan_slab_free+0x131/0x170 [ 34.259411] ? init_rescuer.part.26+0x155/0x190 [ 34.264068] __alloc_workqueue_key+0xef9/0x1190 [ 34.268722] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.274242] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 34.279241] ? put_dec+0xf0/0xf0 [ 34.282588] ? format_decode+0x1b1/0xaf0 [ 34.286630] ? set_precision+0xe0/0xe0 [ 34.290504] ? simple_strtoll+0xa0/0xa0 [ 34.294456] ? graph_lock+0x170/0x170 [ 34.298240] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 34.303757] ? vsnprintf+0x20d/0x1b60 [ 34.307539] ? find_held_lock+0x36/0x1c0 [ 34.311582] ? lock_downgrade+0x8f0/0x8f0 [ 34.315713] ? kasan_check_read+0x11/0x20 [ 34.319845] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 34.324495] bond_init+0x269/0x940 [ 34.328035] ? __dev_get_by_name+0x170/0x170 [ 34.332439] ? bond_arp_rcv+0x11c0/0x11c0 [ 34.336567] ? check_same_owner+0x340/0x340 [ 34.340868] ? rcu_note_context_switch+0x680/0x680 [ 34.345785] ? bond_arp_rcv+0x11c0/0x11c0 [ 34.349915] register_netdevice+0x337/0x1100 [ 34.354306] ? netdev_change_features+0x110/0x110 [ 34.359137] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.364663] ? ns_capable_common+0x13f/0x170 [ 34.369052] ? ns_capable+0x22/0x30 [ 34.372666] bond_newlink+0x49/0xa0 [ 34.376273] ? bond_changelink+0x2360/0x2360 [ 34.380668] rtnl_newlink+0xef4/0x1d50 [ 34.384544] ? rtnl_link_unregister+0x390/0x390 [ 34.389199] ? print_usage_bug+0xc0/0xc0 [ 34.393241] ? __lock_acquire+0x7fc/0x5020 [ 34.397455] ? print_usage_bug+0xc0/0xc0 [ 34.401512] ? graph_lock+0x170/0x170 [ 34.405292] ? print_usage_bug+0xc0/0xc0 [ 34.409334] ? mark_held_locks+0x160/0x160 [ 34.413548] ? __lock_acquire+0x7fc/0x5020 [ 34.417762] ? lock_acquire+0x1e4/0x4f0 [ 34.421717] ? rtnetlink_rcv_msg+0x412/0xc30 [ 34.426112] ? lock_release+0x9f0/0x9f0 [ 34.430080] ? check_same_owner+0x340/0x340 [ 34.434394] ? mutex_trylock+0x2b0/0x2b0 [ 34.438436] ? __lock_acquire+0x7fc/0x5020 [ 34.442662] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.448189] ? refcount_sub_and_test_checked+0x21a/0x350 [ 34.453630] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 34.459156] ? rtnl_get_link+0x170/0x370 [ 34.463203] ? rtnl_dump_all+0x600/0x600 [ 34.467246] ? rcu_is_watching+0x8c/0x150 [ 34.471377] ? rtnl_link_unregister+0x390/0x390 [ 34.476024] rtnetlink_rcv_msg+0x46e/0xc30 [ 34.480240] ? rtnetlink_put_metrics+0x690/0x690 [ 34.484995] netlink_rcv_skb+0x172/0x440 [ 34.489040] ? rtnetlink_put_metrics+0x690/0x690 [ 34.493783] ? netlink_ack+0xbe0/0xbe0 [ 34.497662] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 34.502316] rtnetlink_rcv+0x1c/0x20 [ 34.506011] netlink_unicast+0x5a0/0x760 [ 34.510051] ? netlink_attachskb+0x9a0/0x9a0 [ 34.514444] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.519963] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 34.524961] netlink_sendmsg+0xa18/0xfc0 [ 34.529006] ? netlink_unicast+0x760/0x760 [ 34.533227] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 34.538141] ? apparmor_socket_sendmsg+0x29/0x30 [ 34.542897] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 34.548422] ? security_socket_sendmsg+0x94/0xc0 [ 34.553164] ? netlink_unicast+0x760/0x760 [ 34.557386] sock_sendmsg+0xd5/0x120 [ 34.561080] ___sys_sendmsg+0x7fd/0x930 [ 34.565065] ? copy_msghdr_from_user+0x580/0x580 [ 34.569817] ? lock_downgrade+0x8f0/0x8f0 [ 34.573948] ? __fget_light+0x2f7/0x440 [ 34.577908] ? fget_raw+0x20/0x20 [ 34.581345] ? __fd_install+0x2db/0x880 [ 34.585301] ? get_unused_fd_flags+0x1a0/0x1a0 [ 34.589876] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 34.595408] ? sockfd_lookup_light+0xc5/0x160 [ 34.599886] __sys_sendmsg+0x11d/0x290 [ 34.603759] ? __ia32_sys_shutdown+0x80/0x80 [ 34.608154] ? __x64_sys_futex+0x47f/0x6a0 [ 34.612376] ? do_syscall_64+0x9a/0x820 [ 34.616333] ? do_syscall_64+0x9a/0x820 [ 34.620291] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 34.625391] ? trace_hardirqs_off+0xb8/0x2b0 [ 34.629781] __x64_sys_sendmsg+0x78/0xb0 [ 34.633824] do_syscall_64+0x1b9/0x820 [ 34.637692] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 34.643056] ? syscall_return_slowpath+0x5e0/0x5e0 [ 34.647967] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 34.652965] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 34.657963] ? recalc_sigpending_tsk+0x180/0x180 [ 34.662703] ? kasan_check_write+0x14/0x20 [ 34.666923] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 34.671751] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 34.676920] RIP: 0033:0x457099 [ 34.680100] 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 [ 34.699002] RSP: 002b:00007f5ee9060c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 34.706696] RAX: ffffffffffffffda RBX: 00007f5ee90616d4 RCX: 0000000000457099 [ 34.713948] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 34.721199] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 34.728453] R10: 000000000