[....] 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[ 19.635242] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 21.793631] random: sshd: uninitialized urandom read (32 bytes read) [ 22.013158] random: sshd: uninitialized urandom read (32 bytes read) [ 22.553100] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.56' (ECDSA) to the list of known hosts. [ 28.235674] urandom_read: 1 callbacks suppressed [ 28.235681] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/07 17:54:08 parsed 1 programs [ 29.141820] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/07 17:54:09 executed programs: 0 [ 29.970516] IPVS: ftp: loaded support on port[0] = 21 [ 30.181882] bridge0: port 1(bridge_slave_0) entered blocking state [ 30.188350] bridge0: port 1(bridge_slave_0) entered disabled state [ 30.195902] device bridge_slave_0 entered promiscuous mode [ 30.213541] bridge0: port 2(bridge_slave_1) entered blocking state [ 30.219915] bridge0: port 2(bridge_slave_1) entered disabled state [ 30.227318] device bridge_slave_1 entered promiscuous mode [ 30.242996] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 30.259600] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 30.304535] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 30.323759] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 30.391312] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 30.399038] team0: Port device team_slave_0 added [ 30.416039] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 30.423176] team0: Port device team_slave_1 added [ 30.439724] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 30.458159] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 30.476632] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 30.494819] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 30.622673] bridge0: port 2(bridge_slave_1) entered blocking state [ 30.629123] bridge0: port 2(bridge_slave_1) entered forwarding state [ 30.636122] bridge0: port 1(bridge_slave_0) entered blocking state [ 30.642490] bridge0: port 1(bridge_slave_0) entered forwarding state [ 31.102807] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 31.108920] 8021q: adding VLAN 0 to HW filter on device bond0 [ 31.122779] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 31.163568] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 31.217073] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 31.223647] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 31.232683] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 31.276022] 8021q: adding VLAN 0 to HW filter on device team0 [ 31.602780] [ 31.604446] ====================================================== [ 31.610788] WARNING: possible circular locking dependency detected [ 31.617086] 4.19.0-rc2-next-20180904+ #55 Not tainted [ 31.622255] ------------------------------------------------------ [ 31.628572] syz-executor0/4571 is trying to acquire lock: [ 31.634087] 00000000d9229002 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 31.643353] [ 31.643353] but task is already holding lock: [ 31.649309] 00000000a1f7514e (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 31.657035] [ 31.657035] which lock already depends on the new lock. [ 31.657035] [ 31.665347] [ 31.665347] the existing dependency chain (in reverse order) is: [ 31.672994] [ 31.672994] -> #2 (rtnl_mutex){+.+.}: [ 31.678272] __mutex_lock+0x171/0x1700 [ 31.682666] mutex_lock_nested+0x16/0x20 [ 31.687240] rtnl_lock+0x17/0x20 [ 31.691123] bond_netdev_notify_work+0x44/0xd0 [ 31.696235] process_one_work+0xc73/0x1aa0 [ 31.700985] worker_thread+0x189/0x13c0 [ 31.705477] kthread+0x35a/0x420 [ 31.709347] ret_from_fork+0x3a/0x50 [ 31.713558] [ 31.713558] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 31.721266] process_one_work+0xc0b/0x1aa0 [ 31.726009] worker_thread+0x189/0x13c0 [ 31.730506] kthread+0x35a/0x420 [ 31.734376] ret_from_fork+0x3a/0x50 [ 31.738585] [ 31.738585] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 31.745526] lock_acquire+0x1e4/0x4f0 [ 31.749863] flush_workqueue+0x30a/0x1e10 [ 31.754515] drain_workqueue+0x2a9/0x640 [ 31.759102] destroy_workqueue+0xc6/0x9d0 [ 31.763756] __alloc_workqueue_key+0xef9/0x1190 [ 31.768930] bond_init+0x269/0x940 [ 31.772974] register_netdevice+0x337/0x1100 [ 31.777895] bond_newlink+0x49/0xa0 [ 31.782037] rtnl_newlink+0xef4/0x1d50 [ 31.786429] rtnetlink_rcv_msg+0x46e/0xc30 [ 31.791172] netlink_rcv_skb+0x172/0x440 [ 31.795736] rtnetlink_rcv+0x1c/0x20 [ 31.799952] netlink_unicast+0x5a0/0x760 [ 31.804587] netlink_sendmsg+0xa18/0xfc0 [ 31.809175] sock_sendmsg+0xd5/0x120 [ 31.813396] ___sys_sendmsg+0x7fd/0x930 [ 31.817893] __sys_sendmsg+0x11d/0x290 [ 31.822285] __x64_sys_sendmsg+0x78/0xb0 [ 31.826866] do_syscall_64+0x1b9/0x820 [ 31.831263] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.836950] [ 31.836950] other info that might help us debug this: [ 31.836950] [ 31.845176] Chain exists of: [ 31.845176] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 31.845176] [ 31.858896] Possible unsafe locking scenario: [ 31.858896] [ 31.864935] CPU0 CPU1 [ 31.869577] ---- ---- [ 31.874227] lock(rtnl_mutex); [ 31.877499] lock((work_completion)(&(&nnw->work)->work)); [ 31.885715] lock(rtnl_mutex); [ 31.891503] lock((wq_completion)bond_dev->name); [ 31.896426] [ 31.896426] *** DEADLOCK *** [ 31.896426] [ 31.902469] 1 lock held by syz-executor0/4571: [ 31.907031] #0: 00000000a1f7514e (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 31.915189] [ 31.915189] stack backtrace: [ 31.919681] CPU: 0 PID: 4571 Comm: syz-executor0 Not tainted 4.19.0-rc2-next-20180904+ #55 [ 31.928083] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.937421] Call Trace: [ 31.940009] dump_stack+0x1c9/0x2b4 [ 31.943622] ? dump_stack_print_info.cold.2+0x52/0x52 [ 31.948818] ? vprintk_func+0x81/0x117 [ 31.952693] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 31.958392] ? save_trace+0xe0/0x290 [ 31.962091] __lock_acquire+0x3449/0x5020 [ 31.966234] ? mark_held_locks+0x160/0x160 [ 31.970464] ? __lock_is_held+0xb5/0x140 [ 31.974511] ? update_curr+0x344/0xba0 [ 31.978386] ? print_usage_bug+0xc0/0xc0 [ 31.982432] ? pick_next_task_fair+0x999/0x16e0 [ 31.987083] ? find_held_lock+0x36/0x1c0 [ 31.991128] ? mark_held_locks+0xc9/0x160 [ 31.995267] lock_acquire+0x1e4/0x4f0 [ 31.999059] ? flush_workqueue+0x2db/0x1e10 [ 32.003364] ? lock_release+0x9f0/0x9f0 [ 32.007322] ? lockdep_init_map+0x9/0x10 [ 32.011367] ? __init_waitqueue_head+0x9e/0x150 [ 32.016017] ? init_wait_entry+0x1c0/0x1c0 [ 32.020343] flush_workqueue+0x30a/0x1e10 [ 32.024497] ? flush_workqueue+0x2db/0x1e10 [ 32.028806] ? lock_acquire+0x1e4/0x4f0 [ 32.032765] ? drain_workqueue+0xa9/0x640 [ 32.036899] ? lock_release+0x9f0/0x9f0 [ 32.040865] ? check_same_owner+0x340/0x340 [ 32.045265] ? __schedule+0x884/0x1df0 [ 32.049140] ? __queue_delayed_work+0x390/0x390 [ 32.053806] ? graph_lock+0x170/0x170 [ 32.057606] ? kasan_check_write+0x14/0x20 [ 32.061853] ? __mutex_lock+0x6d0/0x1700 [ 32.065911] ? drain_workqueue+0xa9/0x640 [ 32.070050] ? graph_lock+0x170/0x170 [ 32.073831] ? print_usage_bug+0xc0/0xc0 [ 32.077889] ? find_held_lock+0x36/0x1c0 [ 32.081976] ? lock_downgrade+0x8f0/0x8f0 [ 32.086130] ? schedule+0xfb/0x450 [ 32.089665] ? graph_lock+0x170/0x170 [ 32.093471] ? find_held_lock+0x36/0x1c0 [ 32.097517] ? kasan_check_write+0x14/0x20 [ 32.101738] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 32.106651] ? wait_for_completion+0x8d0/0x8d0 [ 32.111233] ? do_raw_spin_unlock+0xa7/0x2f0 [ 32.115631] ? trace_hardirqs_on+0x2c0/0x2c0 [ 32.120043] drain_workqueue+0x2a9/0x640 [ 32.124087] ? drain_workqueue+0x2a9/0x640 [ 32.128306] ? flush_workqueue+0x1e10/0x1e10 [ 32.132718] ? save_stack+0xa9/0xd0 [ 32.136342] ? save_stack+0x43/0xd0 [ 32.139976] ? __kasan_slab_free+0x11a/0x170 [ 32.144369] ? kasan_slab_free+0xe/0x10 [ 32.148335] ? print_usage_bug+0xc0/0xc0 [ 32.152387] ? bond_init+0x269/0x940 [ 32.156085] ? register_netdevice+0x337/0x1100 [ 32.160649] ? bond_newlink+0x49/0xa0 [ 32.164433] ? rtnl_newlink+0xef4/0x1d50 [ 32.168504] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 32.172898] ? netlink_rcv_skb+0x172/0x440 [ 32.177117] ? rtnetlink_rcv+0x1c/0x20 [ 32.181003] ? netlink_unicast+0x5a0/0x760 [ 32.185232] ? netlink_sendmsg+0xa18/0xfc0 [ 32.189483] ? sock_sendmsg+0xd5/0x120 [ 32.193359] destroy_workqueue+0xc6/0x9d0 [ 32.197519] ? kasan_check_write+0x14/0x20 [ 32.201752] ? wq_watchdog_timer_fn+0x830/0x830 [ 32.206403] ? mark_held_locks+0xc9/0x160 [ 32.210539] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 32.215636] ? kfree+0x111/0x210 [ 32.218990] ? kfree+0x111/0x210 [ 32.222340] ? lockdep_hardirqs_on+0x421/0x5c0 [ 32.226906] ? trace_hardirqs_on+0xbd/0x2c0 [ 32.231220] ? init_rescuer.part.26+0x155/0x190 [ 32.235888] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 32.240988] ? __kasan_slab_free+0x131/0x170 [ 32.245385] ? init_rescuer.part.26+0x155/0x190 [ 32.250127] __alloc_workqueue_key+0xef9/0x1190 [ 32.254790] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.260310] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 32.265311] ? put_dec+0xf0/0xf0 [ 32.268660] ? format_decode+0x1b1/0xaf0 [ 32.272705] ? set_precision+0xe0/0xe0 [ 32.276580] ? simple_strtoll+0xa0/0xa0 [ 32.280536] ? graph_lock+0x170/0x170 [ 32.284426] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.289945] ? vsnprintf+0x20d/0x1b60 [ 32.293732] ? find_held_lock+0x36/0x1c0 [ 32.297777] ? lock_downgrade+0x8f0/0x8f0 [ 32.301914] ? kasan_check_read+0x11/0x20 [ 32.306045] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.310703] bond_init+0x269/0x940 [ 32.314238] ? __dev_get_by_name+0x170/0x170 [ 32.318636] ? bond_arp_rcv+0x11c0/0x11c0 [ 32.322773] ? check_same_owner+0x340/0x340 [ 32.327078] ? rcu_note_context_switch+0x680/0x680 [ 32.332005] ? bond_arp_rcv+0x11c0/0x11c0 [ 32.336136] register_netdevice+0x337/0x1100 [ 32.340538] ? netdev_change_features+0x110/0x110 [ 32.345398] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.350920] ? ns_capable_common+0x13f/0x170 [ 32.355309] ? ns_capable+0x22/0x30 [ 32.358923] bond_newlink+0x49/0xa0 [ 32.362534] ? bond_changelink+0x2360/0x2360 [ 32.366924] rtnl_newlink+0xef4/0x1d50 [ 32.370823] ? rtnl_link_unregister+0x390/0x390 [ 32.375501] ? print_usage_bug+0xc0/0xc0 [ 32.379548] ? __lock_acquire+0x7fc/0x5020 [ 32.383765] ? print_usage_bug+0xc0/0xc0 [ 32.387808] ? graph_lock+0x170/0x170 [ 32.391590] ? print_usage_bug+0xc0/0xc0 [ 32.395633] ? mark_held_locks+0x160/0x160 [ 32.399859] ? __lock_acquire+0x7fc/0x5020 [ 32.404082] ? lock_acquire+0x1e4/0x4f0 [ 32.408042] ? rtnetlink_rcv_msg+0x412/0xc30 [ 32.412475] ? lock_release+0x9f0/0x9f0 [ 32.416435] ? check_same_owner+0x340/0x340 [ 32.420753] ? mutex_trylock+0x2b0/0x2b0 [ 32.424796] ? __lock_acquire+0x7fc/0x5020 [ 32.429037] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.434586] ? refcount_sub_and_test_checked+0x21a/0x350 [ 32.440032] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.445554] ? rtnl_get_link+0x170/0x370 [ 32.449598] ? rtnl_dump_all+0x600/0x600 [ 32.453643] ? rcu_is_watching+0x8c/0x150 [ 32.457776] ? rtnl_link_unregister+0x390/0x390 [ 32.462430] rtnetlink_rcv_msg+0x46e/0xc30 [ 32.466650] ? rtnetlink_put_metrics+0x690/0x690 [ 32.471421] netlink_rcv_skb+0x172/0x440 [ 32.475488] ? rtnetlink_put_metrics+0x690/0x690 [ 32.480235] ? netlink_ack+0xbe0/0xbe0 [ 32.484133] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 32.488802] rtnetlink_rcv+0x1c/0x20 [ 32.492501] netlink_unicast+0x5a0/0x760 [ 32.496548] ? netlink_attachskb+0x9a0/0x9a0 [ 32.500971] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.506496] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 32.511494] netlink_sendmsg+0xa18/0xfc0 [ 32.515537] ? netlink_unicast+0x760/0x760 [ 32.519755] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 32.524668] ? apparmor_socket_sendmsg+0x29/0x30 [ 32.529409] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 32.534929] ? security_socket_sendmsg+0x94/0xc0 [ 32.539669] ? netlink_unicast+0x760/0x760 [ 32.543887] sock_sendmsg+0xd5/0x120 [ 32.547628] ___sys_sendmsg+0x7fd/0x930 [ 32.551612] ? copy_msghdr_from_user+0x580/0x580 [ 32.556350] ? lock_downgrade+0x8f0/0x8f0 [ 32.560482] ? __fget_light+0x2f7/0x440 [ 32.564460] ? fget_raw+0x20/0x20 [ 32.567901] ? __fd_install+0x2db/0x880 [ 32.571869] ? get_unused_fd_flags+0x1a0/0x1a0 [ 32.576441] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 32.581959] ? sockfd_lookup_light+0xc5/0x160 [ 32.586436] __sys_sendmsg+0x11d/0x290 [ 32.590309] ? __ia32_sys_shutdown+0x80/0x80 [ 32.594703] ? __x64_sys_futex+0x47f/0x6a0 [ 32.598924] ? do_syscall_64+0x9a/0x820 [ 32.602880] ? do_syscall_64+0x9a/0x820 [ 32.606838] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 32.611938] ? ksys_ioctl+0x81/0xd0 [ 32.615547] __x64_sys_sendmsg+0x78/0xb0 [ 32.619617] do_syscall_64+0x1b9/0x820 [ 32.623499] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 32.628880] ? syscall_return_slowpath+0x5e0/0x5e0 [ 32.633795] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 32.638792] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 32.643790] ? recalc_sigpending_tsk+0x180/0x180 [ 32.648529] ? kasan_check_write+0x14/0x20 [ 32.652750] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 32.657578] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 32.662746] RIP: 0033:0x457099 [ 32.665926] 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 [ 32.684810] RSP: 002b:00007f648c3dcc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 32.692496] RAX: ffffffffffffffda RBX: 00007f648c3dd6d4 RCX: 0000000000457099 [ 32.699769] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000005 [ 32.707019] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 32.714269] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 32.721541] R13: 00000000004d4bf0 R14: 00000000004c9133 R15: 0000000000000000 2018/09/07 17:54:14 executed programs: 103 2018/09/07 17:54:19 executed programs: 320