[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 21.658411] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.834107] random: sshd: uninitialized urandom read (32 bytes read) [ 27.263877] random: sshd: uninitialized urandom read (32 bytes read) [ 27.816376] random: sshd: uninitialized urandom read (32 bytes read) [ 180.996900] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.15.193' (ECDSA) to the list of known hosts. [ 186.543720] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/26 23:22:32 parsed 1 programs [ 187.758234] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/26 23:22:33 executed programs: 0 [ 188.895981] IPVS: ftp: loaded support on port[0] = 21 [ 189.119951] bridge0: port 1(bridge_slave_0) entered blocking state [ 189.126520] bridge0: port 1(bridge_slave_0) entered disabled state [ 189.134471] device bridge_slave_0 entered promiscuous mode [ 189.151262] bridge0: port 2(bridge_slave_1) entered blocking state [ 189.157645] bridge0: port 2(bridge_slave_1) entered disabled state [ 189.165446] device bridge_slave_1 entered promiscuous mode [ 189.181535] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 189.199513] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 189.245502] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 189.265445] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 189.334928] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 189.342547] team0: Port device team_slave_0 added [ 189.357892] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 189.364983] team0: Port device team_slave_1 added [ 189.380948] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 189.401221] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 189.418699] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 189.437497] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 189.568008] bridge0: port 2(bridge_slave_1) entered blocking state [ 189.574496] bridge0: port 2(bridge_slave_1) entered forwarding state [ 189.581606] bridge0: port 1(bridge_slave_0) entered blocking state [ 189.588009] bridge0: port 1(bridge_slave_0) entered forwarding state [ 190.045957] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 190.052068] 8021q: adding VLAN 0 to HW filter on device bond0 [ 190.099392] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 190.110699] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 190.150566] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 190.156752] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 190.164297] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 190.204611] 8021q: adding VLAN 0 to HW filter on device team0 [ 190.488090] [ 190.489746] ====================================================== [ 190.496040] WARNING: possible circular locking dependency detected [ 190.502341] 4.18.0-next-20180824+ #47 Not tainted [ 190.507160] ------------------------------------------------------ [ 190.513456] syz-executor0/4660 is trying to acquire lock: [ 190.518968] 00000000a195c576 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 190.528231] [ 190.528231] but task is already holding lock: [ 190.534182] 00000000a7e17b58 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 190.541883] [ 190.541883] which lock already depends on the new lock. [ 190.541883] [ 190.550185] [ 190.550185] the existing dependency chain (in reverse order) is: [ 190.557784] [ 190.557784] -> #2 (rtnl_mutex){+.+.}: [ 190.563053] __mutex_lock+0x171/0x1700 [ 190.567439] mutex_lock_nested+0x16/0x20 [ 190.572002] rtnl_lock+0x17/0x20 [ 190.575873] bond_netdev_notify_work+0x44/0xd0 [ 190.581083] process_one_work+0xc73/0x1aa0 [ 190.585831] worker_thread+0x189/0x13c0 [ 190.590315] kthread+0x35a/0x420 [ 190.594183] ret_from_fork+0x3a/0x50 [ 190.598403] [ 190.598403] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 190.606107] process_one_work+0xc0b/0x1aa0 [ 190.610843] worker_thread+0x189/0x13c0 [ 190.615318] kthread+0x35a/0x420 [ 190.619187] ret_from_fork+0x3a/0x50 [ 190.623404] [ 190.623404] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 190.630384] lock_acquire+0x1e4/0x4f0 [ 190.634696] flush_workqueue+0x30a/0x1e10 [ 190.639350] drain_workqueue+0x2a9/0x640 [ 190.643960] destroy_workqueue+0xc6/0x9d0 [ 190.648624] __alloc_workqueue_key+0xef9/0x1190 [ 190.653799] bond_init+0x269/0x940 [ 190.657891] register_netdevice+0x337/0x1100 [ 190.662808] bond_newlink+0x49/0xa0 [ 190.667062] rtnl_newlink+0xef4/0x1d50 [ 190.671455] rtnetlink_rcv_msg+0x46e/0xc30 [ 190.676195] netlink_rcv_skb+0x172/0x440 [ 190.680855] rtnetlink_rcv+0x1c/0x20 [ 190.685079] netlink_unicast+0x5a0/0x760 [ 190.689640] netlink_sendmsg+0xa18/0xfc0 [ 190.694390] sock_sendmsg+0xd5/0x120 [ 190.698613] ___sys_sendmsg+0x7fd/0x930 [ 190.703087] __sys_sendmsg+0x11d/0x290 [ 190.707477] __x64_sys_sendmsg+0x78/0xb0 [ 190.712043] do_syscall_64+0x1b9/0x820 [ 190.716437] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 190.722168] [ 190.722168] other info that might help us debug this: [ 190.722168] [ 190.730318] Chain exists of: [ 190.730318] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 190.730318] [ 190.744020] Possible unsafe locking scenario: [ 190.744020] [ 190.750058] CPU0 CPU1 [ 190.754703] ---- ---- [ 190.759346] lock(rtnl_mutex); [ 190.762612] lock((work_completion)(&(&nnw->work)->work)); [ 190.770971] lock(rtnl_mutex); [ 190.776751] lock((wq_completion)bond_dev->name); [ 190.781664] [ 190.781664] *** DEADLOCK *** [ 190.781664] [ 190.787709] 1 lock held by syz-executor0/4660: [ 190.792271] #0: 00000000a7e17b58 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 190.800410] [ 190.800410] stack backtrace: [ 190.804892] CPU: 1 PID: 4660 Comm: syz-executor0 Not tainted 4.18.0-next-20180824+ #47 [ 190.812921] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 190.822253] Call Trace: [ 190.824823] dump_stack+0x1c9/0x2b4 [ 190.828433] ? dump_stack_print_info.cold.2+0x52/0x52 [ 190.833606] ? vprintk_func+0x81/0x117 [ 190.837477] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 190.843171] ? save_trace+0xe0/0x290 [ 190.846911] __lock_acquire+0x3449/0x5020 [ 190.851048] ? mark_held_locks+0x160/0x160 [ 190.855270] ? __lock_is_held+0xb5/0x140 [ 190.859315] ? update_curr+0x344/0xba0 [ 190.863184] ? __account_cfs_rq_runtime+0x770/0x770 [ 190.868183] ? lock_downgrade+0x8f0/0x8f0 [ 190.872313] lock_acquire+0x1e4/0x4f0 [ 190.876097] ? flush_workqueue+0x2db/0x1e10 [ 190.880404] ? lock_release+0x9f0/0x9f0 [ 190.884359] ? lockdep_init_map+0x9/0x10 [ 190.888410] ? __init_waitqueue_head+0x9e/0x150 [ 190.893057] ? init_wait_entry+0x1c0/0x1c0 [ 190.897275] flush_workqueue+0x30a/0x1e10 [ 190.901404] ? flush_workqueue+0x2db/0x1e10 [ 190.905706] ? lock_acquire+0x1e4/0x4f0 [ 190.909663] ? drain_workqueue+0xa9/0x640 [ 190.913791] ? lock_release+0x9f0/0x9f0 [ 190.917746] ? check_same_owner+0x340/0x340 [ 190.922047] ? task_numa_migrate+0x28e0/0x28e0 [ 190.926612] ? __queue_delayed_work+0x390/0x390 [ 190.931259] ? graph_lock+0x170/0x170 [ 190.935158] ? kasan_check_write+0x14/0x20 [ 190.939383] ? __mutex_lock+0x6d0/0x1700 [ 190.943438] ? drain_workqueue+0xa9/0x640 [ 190.947580] ? graph_lock+0x170/0x170 [ 190.951363] ? print_usage_bug+0xc0/0xc0 [ 190.955412] ? find_held_lock+0x36/0x1c0 [ 190.959458] ? lock_downgrade+0x8f0/0x8f0 [ 190.963586] ? graph_lock+0x170/0x170 [ 190.967366] ? graph_lock+0x170/0x170 [ 190.971152] ? find_held_lock+0x36/0x1c0 [ 190.975195] ? kasan_check_write+0x14/0x20 [ 190.979411] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 190.984319] ? wait_for_completion+0x8d0/0x8d0 [ 190.988958] ? do_raw_spin_unlock+0xa7/0x2f0 [ 190.993364] ? trace_hardirqs_on+0x2c0/0x2c0 [ 190.997761] drain_workqueue+0x2a9/0x640 [ 191.001805] ? drain_workqueue+0x2a9/0x640 [ 191.006023] ? flush_workqueue+0x1e10/0x1e10 [ 191.010411] ? save_stack+0xa9/0xd0 [ 191.014030] ? save_stack+0x43/0xd0 [ 191.017643] ? __kasan_slab_free+0x11a/0x170 [ 191.022032] ? kasan_slab_free+0xe/0x10 [ 191.025986] ? print_usage_bug+0xc0/0xc0 [ 191.030029] ? bond_init+0x269/0x940 [ 191.033727] ? register_netdevice+0x337/0x1100 [ 191.038288] ? bond_newlink+0x49/0xa0 [ 191.042069] ? rtnl_newlink+0xef4/0x1d50 [ 191.046117] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 191.050510] ? netlink_rcv_skb+0x172/0x440 [ 191.054774] ? rtnetlink_rcv+0x1c/0x20 [ 191.058652] ? netlink_unicast+0x5a0/0x760 [ 191.062870] ? netlink_sendmsg+0xa18/0xfc0 [ 191.067083] ? sock_sendmsg+0xd5/0x120 [ 191.070955] destroy_workqueue+0xc6/0x9d0 [ 191.075095] ? kasan_check_write+0x14/0x20 [ 191.079317] ? wq_watchdog_timer_fn+0x830/0x830 [ 191.083967] ? mark_held_locks+0xc9/0x160 [ 191.088105] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 191.093193] ? kfree+0x111/0x210 [ 191.096539] ? kfree+0x111/0x210 [ 191.099888] ? lockdep_hardirqs_on+0x421/0x5c0 [ 191.104450] ? trace_hardirqs_on+0xbd/0x2c0 [ 191.108751] ? init_rescuer.part.26+0x155/0x190 [ 191.113408] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 191.118498] ? __kasan_slab_free+0x131/0x170 [ 191.122888] ? init_rescuer.part.26+0x155/0x190 [ 191.127647] __alloc_workqueue_key+0xef9/0x1190 [ 191.132367] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.137901] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 191.142901] ? put_dec+0xf0/0xf0 [ 191.146257] ? format_decode+0x1b1/0xaf0 [ 191.150301] ? set_precision+0xe0/0xe0 [ 191.154232] ? simple_strtoll+0xa0/0xa0 [ 191.158200] ? graph_lock+0x170/0x170 [ 191.161984] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 191.167498] ? vsnprintf+0x20d/0x1b60 [ 191.171279] ? find_held_lock+0x36/0x1c0 [ 191.175320] ? lock_downgrade+0x8f0/0x8f0 [ 191.179450] ? kasan_check_read+0x11/0x20 [ 191.183583] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 191.188234] bond_init+0x269/0x940 [ 191.191758] ? __dev_get_by_name+0x170/0x170 [ 191.196156] ? bond_arp_rcv+0x11c0/0x11c0 [ 191.200296] ? check_same_owner+0x340/0x340 [ 191.204646] ? rcu_note_context_switch+0x680/0x680 [ 191.209577] ? bond_arp_rcv+0x11c0/0x11c0 [ 191.213712] register_netdevice+0x337/0x1100 [ 191.218107] ? netdev_change_features+0x110/0x110 [ 191.222935] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.228452] ? ns_capable_common+0x13f/0x170 [ 191.232995] bond_newlink+0x49/0xa0 [ 191.236610] ? bond_changelink+0x2360/0x2360 [ 191.241001] rtnl_newlink+0xef4/0x1d50 [ 191.244982] ? rtnl_link_unregister+0x390/0x390 [ 191.249638] ? print_usage_bug+0xc0/0xc0 [ 191.253680] ? __lock_acquire+0x7fc/0x5020 [ 191.257896] ? print_usage_bug+0xc0/0xc0 [ 191.261937] ? graph_lock+0x170/0x170 [ 191.265717] ? print_usage_bug+0xc0/0xc0 [ 191.269756] ? mark_held_locks+0x160/0x160 [ 191.273977] ? __lock_acquire+0x7fc/0x5020 [ 191.278197] ? lock_acquire+0x1e4/0x4f0 [ 191.282223] ? rtnetlink_rcv_msg+0x412/0xc30 [ 191.286618] ? lock_release+0x9f0/0x9f0 [ 191.290579] ? check_same_owner+0x340/0x340 [ 191.294886] ? mutex_trylock+0x2b0/0x2b0 [ 191.298927] ? __lock_acquire+0x7fc/0x5020 [ 191.303143] ? graph_lock+0x170/0x170 [ 191.306998] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 191.312524] ? rtnl_get_link+0x170/0x370 [ 191.316571] ? rtnl_dump_all+0x600/0x600 [ 191.320612] ? rcu_is_watching+0x8c/0x150 [ 191.324744] ? rtnl_link_unregister+0x390/0x390 [ 191.329401] rtnetlink_rcv_msg+0x46e/0xc30 [ 191.333622] ? rtnetlink_put_metrics+0x690/0x690 [ 191.338361] netlink_rcv_skb+0x172/0x440 [ 191.342410] ? rtnetlink_put_metrics+0x690/0x690 [ 191.347155] ? netlink_ack+0xbe0/0xbe0 [ 191.351029] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 191.357997] rtnetlink_rcv+0x1c/0x20 [ 191.361699] netlink_unicast+0x5a0/0x760 [ 191.365746] ? netlink_attachskb+0x9a0/0x9a0 [ 191.370143] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 191.375676] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 191.380686] netlink_sendmsg+0xa18/0xfc0 [ 191.384735] ? netlink_unicast+0x760/0x760 [ 191.388957] ? move_addr_to_kernel.part.18+0x100/0x100 [ 191.394224] ? security_socket_sendmsg+0x94/0xc0 [ 191.398965] ? netlink_unicast+0x760/0x760 [ 191.403192] sock_sendmsg+0xd5/0x120 [ 191.406893] ___sys_sendmsg+0x7fd/0x930 [ 191.410861] ? copy_msghdr_from_user+0x580/0x580 [ 191.415602] ? lock_downgrade+0x8f0/0x8f0 [ 191.419739] ? __fget_light+0x2f7/0x440 [ 191.423698] ? fget_raw+0x20/0x20 [ 191.427135] ? __fd_install+0x2db/0x880 [ 191.431100] ? get_unused_fd_flags+0x1a0/0x1a0 [ 191.435670] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 191.441196] ? sockfd_lookup_light+0xc5/0x160 [ 191.445675] __sys_sendmsg+0x11d/0x290 [ 191.449555] ? __ia32_sys_shutdown+0x80/0x80 [ 191.453966] ? _raw_spin_unlock_irqrestore+0x74/0xc0 [ 191.459058] ? __x64_sys_futex+0x47f/0x6a0 [ 191.463319] ? do_syscall_64+0x9a/0x820 [ 191.467303] ? do_syscall_64+0x9a/0x820 [ 191.471262] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 191.476348] ? trace_hardirqs_off+0xb8/0x2b0 [ 191.480741] __x64_sys_sendmsg+0x78/0xb0 [ 191.484789] do_syscall_64+0x1b9/0x820 [ 191.488660] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 191.494008] ? syscall_return_slowpath+0x5e0/0x5e0 [ 191.498930] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 191.503978] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 191.508982] ? recalc_sigpending_tsk+0x180/0x180 [ 191.513726] ? kasan_check_write+0x14/0x20 [ 191.517946] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 191.522796] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 191.527967] RIP: 0033:0x457089 [ 191.531145] 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 [ 191.550040] RSP: 002b:00007f8268da7c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 191.557747] RAX: ffffffffffffffda RBX: 00007f8268da86d4 RCX: 0000000000457089 [ 191.564999] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 191.572253] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 191.579511] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 191.586766] R13: 00000000004d4188 R14: 00000000004c8b53 R15: 000000000