[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.646774] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 26.910930] random: sshd: uninitialized urandom read (32 bytes read) [ 27.285027] random: sshd: uninitialized urandom read (32 bytes read) [ 27.838582] random: sshd: uninitialized urandom read (32 bytes read) [ 143.043709] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.0.37' (ECDSA) to the list of known hosts. [ 148.599059] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/31 09:18:18 parsed 1 programs [ 149.592344] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/31 09:18:19 executed programs: 0 [ 150.544070] IPVS: ftp: loaded support on port[0] = 21 [ 150.764905] bridge0: port 1(bridge_slave_0) entered blocking state [ 150.771496] bridge0: port 1(bridge_slave_0) entered disabled state [ 150.779010] device bridge_slave_0 entered promiscuous mode [ 150.796800] bridge0: port 2(bridge_slave_1) entered blocking state [ 150.803196] bridge0: port 2(bridge_slave_1) entered disabled state [ 150.810937] device bridge_slave_1 entered promiscuous mode [ 150.827546] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 150.844380] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 150.888210] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 150.907173] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 150.972888] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 150.980148] team0: Port device team_slave_0 added [ 150.995311] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 151.002618] team0: Port device team_slave_1 added [ 151.018918] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 151.037088] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 151.054601] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 151.073399] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 151.200976] bridge0: port 2(bridge_slave_1) entered blocking state [ 151.207650] bridge0: port 2(bridge_slave_1) entered forwarding state [ 151.214474] bridge0: port 1(bridge_slave_0) entered blocking state [ 151.220836] bridge0: port 1(bridge_slave_0) entered forwarding state [ 151.668222] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 151.674353] 8021q: adding VLAN 0 to HW filter on device bond0 [ 151.714087] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 151.727781] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 151.772828] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 151.779128] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 151.787055] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 151.827087] 8021q: adding VLAN 0 to HW filter on device team0 [ 152.125952] [ 152.127596] ====================================================== [ 152.134022] WARNING: possible circular locking dependency detected [ 152.140317] 4.19.0-rc1+ #216 Not tainted [ 152.144350] ------------------------------------------------------ [ 152.150640] syz-executor0/4901 is trying to acquire lock: [ 152.156149] 000000000debd27b ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 152.165409] [ 152.165409] but task is already holding lock: [ 152.171354] 00000000f534ffd2 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 152.179046] [ 152.179046] which lock already depends on the new lock. [ 152.179046] [ 152.187336] [ 152.187336] the existing dependency chain (in reverse order) is: [ 152.194931] [ 152.194931] -> #2 (rtnl_mutex){+.+.}: [ 152.200199] __mutex_lock+0x171/0x1700 [ 152.204582] mutex_lock_nested+0x16/0x20 [ 152.209139] rtnl_lock+0x17/0x20 [ 152.213003] bond_netdev_notify_work+0x44/0xd0 [ 152.218100] process_one_work+0xc73/0x1aa0 [ 152.222838] worker_thread+0x189/0x13c0 [ 152.227319] kthread+0x35a/0x420 [ 152.231183] ret_from_fork+0x3a/0x50 [ 152.235389] [ 152.235389] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 152.243095] process_one_work+0xc0b/0x1aa0 [ 152.247828] worker_thread+0x189/0x13c0 [ 152.252299] kthread+0x35a/0x420 [ 152.256164] ret_from_fork+0x3a/0x50 [ 152.260371] [ 152.260371] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 152.267281] lock_acquire+0x1e4/0x4f0 [ 152.271577] flush_workqueue+0x30a/0x1e10 [ 152.276223] drain_workqueue+0x2a9/0x640 [ 152.280781] destroy_workqueue+0xc6/0x9d0 [ 152.285430] __alloc_workqueue_key+0xef9/0x1190 [ 152.290598] bond_init+0x269/0x940 [ 152.294639] register_netdevice+0x337/0x1100 [ 152.299553] bond_newlink+0x49/0xa0 [ 152.303685] rtnl_newlink+0xef4/0x1d50 [ 152.308071] rtnetlink_rcv_msg+0x46e/0xc30 [ 152.312803] netlink_rcv_skb+0x172/0x440 [ 152.317389] rtnetlink_rcv+0x1c/0x20 [ 152.321603] netlink_unicast+0x5a0/0x760 [ 152.326321] netlink_sendmsg+0xa18/0xfc0 [ 152.331144] sock_sendmsg+0xd5/0x120 [ 152.335410] ___sys_sendmsg+0x7fd/0x930 [ 152.339891] __sys_sendmsg+0x11d/0x290 [ 152.344288] __x64_sys_sendmsg+0x78/0xb0 [ 152.348854] do_syscall_64+0x1b9/0x820 [ 152.353247] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 152.358934] [ 152.358934] other info that might help us debug this: [ 152.358934] [ 152.367060] Chain exists of: [ 152.367060] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 152.367060] [ 152.380749] Possible unsafe locking scenario: [ 152.380749] [ 152.386786] CPU0 CPU1 [ 152.391429] ---- ---- [ 152.396090] lock(rtnl_mutex); [ 152.399358] lock((work_completion)(&(&nnw->work)->work)); [ 152.407590] lock(rtnl_mutex); [ 152.413366] lock((wq_completion)bond_dev->name); [ 152.418282] [ 152.418282] *** DEADLOCK *** [ 152.418282] [ 152.424333] 1 lock held by syz-executor0/4901: [ 152.428896] #0: 00000000f534ffd2 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 152.437098] [ 152.437098] stack backtrace: [ 152.441586] CPU: 1 PID: 4901 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #216 [ 152.448850] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 152.458219] Call Trace: [ 152.460874] dump_stack+0x1c9/0x2b4 [ 152.464496] ? dump_stack_print_info.cold.2+0x52/0x52 [ 152.469692] ? vprintk_func+0x81/0x117 [ 152.473574] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 152.479267] ? save_trace+0xe0/0x290 [ 152.482961] __lock_acquire+0x3449/0x5020 [ 152.487092] ? mark_held_locks+0x160/0x160 [ 152.491313] ? mark_held_locks+0x160/0x160 [ 152.495538] ? __lock_is_held+0xb5/0x140 [ 152.499584] ? __account_cfs_rq_runtime+0x770/0x770 [ 152.504595] ? set_next_entity+0x2f0/0xa80 [ 152.508813] lock_acquire+0x1e4/0x4f0 [ 152.512598] ? flush_workqueue+0x2db/0x1e10 [ 152.516901] ? lock_release+0x9f0/0x9f0 [ 152.520872] ? lockdep_init_map+0x9/0x10 [ 152.524929] ? __init_waitqueue_head+0x9e/0x150 [ 152.529592] ? init_wait_entry+0x1c0/0x1c0 [ 152.533818] flush_workqueue+0x30a/0x1e10 [ 152.537952] ? flush_workqueue+0x2db/0x1e10 [ 152.542255] ? lock_acquire+0x1e4/0x4f0 [ 152.546212] ? drain_workqueue+0xa9/0x640 [ 152.550342] ? lock_release+0x9f0/0x9f0 [ 152.554298] ? check_same_owner+0x340/0x340 [ 152.558693] ? __queue_delayed_work+0x390/0x390 [ 152.563409] ? graph_lock+0x170/0x170 [ 152.567200] ? kasan_check_write+0x14/0x20 [ 152.571420] ? __mutex_lock+0x6d0/0x1700 [ 152.575481] ? drain_workqueue+0xa9/0x640 [ 152.579613] ? finish_task_switch+0x2ca/0x870 [ 152.584091] ? find_held_lock+0x36/0x1c0 [ 152.588133] ? lock_downgrade+0x8f0/0x8f0 [ 152.592325] ? __schedule+0x884/0x1df0 [ 152.596198] ? graph_lock+0x170/0x170 [ 152.599979] ? find_held_lock+0x36/0x1c0 [ 152.604027] ? kasan_check_write+0x14/0x20 [ 152.608465] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 152.613372] ? wait_for_completion+0x8d0/0x8d0 [ 152.617947] ? do_raw_spin_unlock+0xa7/0x2f0 [ 152.622334] ? trace_hardirqs_on+0x2c0/0x2c0 [ 152.626720] drain_workqueue+0x2a9/0x640 [ 152.630770] ? drain_workqueue+0x2a9/0x640 [ 152.634979] ? flush_workqueue+0x1e10/0x1e10 [ 152.639374] ? save_stack+0xa9/0xd0 [ 152.643037] ? save_stack+0x43/0xd0 [ 152.646651] ? __kasan_slab_free+0x11a/0x170 [ 152.651050] ? kasan_slab_free+0xe/0x10 [ 152.655001] ? print_usage_bug+0xc0/0xc0 [ 152.659041] ? bond_init+0x269/0x940 [ 152.662732] ? register_netdevice+0x337/0x1100 [ 152.667317] ? bond_newlink+0x49/0xa0 [ 152.671095] ? rtnl_newlink+0xef4/0x1d50 [ 152.675136] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 152.679520] ? netlink_rcv_skb+0x172/0x440 [ 152.683731] ? rtnetlink_rcv+0x1c/0x20 [ 152.687594] ? netlink_unicast+0x5a0/0x760 [ 152.691811] ? netlink_sendmsg+0xa18/0xfc0 [ 152.696035] ? sock_sendmsg+0xd5/0x120 [ 152.699921] destroy_workqueue+0xc6/0x9d0 [ 152.704048] ? kasan_check_write+0x14/0x20 [ 152.708265] ? wq_watchdog_timer_fn+0x830/0x830 [ 152.712910] ? mark_held_locks+0xc9/0x160 [ 152.717034] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 152.722118] ? kfree+0x111/0x210 [ 152.725460] ? kfree+0x111/0x210 [ 152.728818] ? lockdep_hardirqs_on+0x421/0x5c0 [ 152.733391] ? trace_hardirqs_on+0xbd/0x2c0 [ 152.737701] ? init_rescuer.part.26+0x155/0x190 [ 152.742415] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 152.747505] ? __kasan_slab_free+0x131/0x170 [ 152.751893] ? init_rescuer.part.26+0x155/0x190 [ 152.756552] __alloc_workqueue_key+0xef9/0x1190 [ 152.761204] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 152.766732] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 152.771729] ? put_dec+0xf0/0xf0 [ 152.775075] ? format_decode+0x1b1/0xaf0 [ 152.779114] ? set_precision+0xe0/0xe0 [ 152.782982] ? simple_strtoll+0xa0/0xa0 [ 152.786935] ? graph_lock+0x170/0x170 [ 152.790718] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 152.796236] ? vsnprintf+0x20d/0x1b60 [ 152.800017] ? find_held_lock+0x36/0x1c0 [ 152.804063] ? lock_downgrade+0x8f0/0x8f0 [ 152.808195] ? kasan_check_read+0x11/0x20 [ 152.812327] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 152.817024] bond_init+0x269/0x940 [ 152.820654] ? __dev_get_by_name+0x170/0x170 [ 152.825044] ? bond_arp_rcv+0x11c0/0x11c0 [ 152.829169] ? check_same_owner+0x340/0x340 [ 152.833467] ? rcu_note_context_switch+0x680/0x680 [ 152.838386] ? bond_arp_rcv+0x11c0/0x11c0 [ 152.842512] register_netdevice+0x337/0x1100 [ 152.846899] ? netdev_change_features+0x110/0x110 [ 152.851724] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 152.857247] ? ns_capable_common+0x13f/0x170 [ 152.861646] bond_newlink+0x49/0xa0 [ 152.865250] ? bond_changelink+0x2360/0x2360 [ 152.869640] rtnl_newlink+0xef4/0x1d50 [ 152.873506] ? rtnl_link_unregister+0x390/0x390 [ 152.878153] ? print_usage_bug+0xc0/0xc0 [ 152.882188] ? __lock_acquire+0x7fc/0x5020 [ 152.886398] ? print_usage_bug+0xc0/0xc0 [ 152.890442] ? graph_lock+0x170/0x170 [ 152.894225] ? print_usage_bug+0xc0/0xc0 [ 152.898275] ? mark_held_locks+0x160/0x160 [ 152.902495] ? __lock_acquire+0x7fc/0x5020 [ 152.906709] ? lock_acquire+0x1e4/0x4f0 [ 152.910663] ? rtnetlink_rcv_msg+0x412/0xc30 [ 152.915049] ? lock_release+0x9f0/0x9f0 [ 152.919002] ? check_same_owner+0x340/0x340 [ 152.923307] ? mutex_trylock+0x2b0/0x2b0 [ 152.927343] ? __lock_acquire+0x7fc/0x5020 [ 152.931562] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 152.937078] ? refcount_sub_and_test_checked+0x21a/0x350 [ 152.942513] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 152.948027] ? rtnl_get_link+0x170/0x370 [ 152.952068] ? rtnl_dump_all+0x600/0x600 [ 152.956128] ? rcu_is_watching+0x8c/0x150 [ 152.960255] ? rtnl_link_unregister+0x390/0x390 [ 152.964902] rtnetlink_rcv_msg+0x46e/0xc30 [ 152.969118] ? rtnetlink_put_metrics+0x690/0x690 [ 152.973864] netlink_rcv_skb+0x172/0x440 [ 152.977906] ? rtnetlink_put_metrics+0x690/0x690 [ 152.982640] ? netlink_ack+0xbe0/0xbe0 [ 152.986511] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 152.991160] rtnetlink_rcv+0x1c/0x20 [ 152.994854] netlink_unicast+0x5a0/0x760 [ 152.998893] ? netlink_attachskb+0x9a0/0x9a0 [ 153.003282] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 153.008800] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 153.013793] netlink_sendmsg+0xa18/0xfc0 [ 153.017845] ? netlink_unicast+0x760/0x760 [ 153.022058] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 153.026964] ? apparmor_socket_sendmsg+0x29/0x30 [ 153.031699] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 153.037299] ? security_socket_sendmsg+0x94/0xc0 [ 153.042032] ? netlink_unicast+0x760/0x760 [ 153.046243] sock_sendmsg+0xd5/0x120 [ 153.049934] ___sys_sendmsg+0x7fd/0x930 [ 153.053888] ? copy_msghdr_from_user+0x580/0x580 [ 153.058621] ? lock_downgrade+0x8f0/0x8f0 [ 153.062745] ? __fget_light+0x2f7/0x440 [ 153.066712] ? fget_raw+0x20/0x20 [ 153.070141] ? __fd_install+0x2db/0x880 [ 153.074103] ? get_unused_fd_flags+0x1a0/0x1a0 [ 153.078676] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 153.084190] ? sockfd_lookup_light+0xc5/0x160 [ 153.088681] __sys_sendmsg+0x11d/0x290 [ 153.092595] ? __ia32_sys_shutdown+0x80/0x80 [ 153.097043] ? __x64_sys_futex+0x47f/0x6a0 [ 153.101264] ? do_syscall_64+0x9a/0x820 [ 153.105218] ? do_syscall_64+0x9a/0x820 [ 153.109182] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 153.114262] ? trace_hardirqs_off+0xb8/0x2b0 [ 153.118651] __x64_sys_sendmsg+0x78/0xb0 [ 153.122705] do_syscall_64+0x1b9/0x820 [ 153.126604] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 153.131951] ? syscall_return_slowpath+0x5e0/0x5e0 [ 153.136900] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 153.141903] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 153.146902] ? recalc_sigpending_tsk+0x180/0x180 [ 153.151641] ? kasan_check_write+0x14/0x20 [ 153.155869] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 153.160701] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 153.165874] RIP: 0033:0x457099 [ 153.169053] 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 [ 153.187968] RSP: 002b:00007f527dfdcc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 153.195658] RAX: ffffffffffffffda RBX: 00007f527dfdd6d4 RCX: 0000000000457099 [ 153.202910] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 153.210159] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 153.217409] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 153.224664] R13: 00000000004d4890 R14: 00000000004c8ee5 R15: 000000000