[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 22.668954] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 28.680097] random: sshd: uninitialized urandom read (32 bytes read) [ 28.907681] random: sshd: uninitialized urandom read (32 bytes read) [ 29.460610] random: sshd: uninitialized urandom read (32 bytes read) [ 103.645114] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.4' (ECDSA) to the list of known hosts. [ 109.368882] random: sshd: uninitialized urandom read (32 bytes read) 2018/08/31 23:28:08 parsed 1 programs [ 110.489189] random: cc1: uninitialized urandom read (8 bytes read) 2018/08/31 23:28:09 executed programs: 0 [ 111.526395] IPVS: ftp: loaded support on port[0] = 21 [ 111.748030] bridge0: port 1(bridge_slave_0) entered blocking state [ 111.754509] bridge0: port 1(bridge_slave_0) entered disabled state [ 111.762040] device bridge_slave_0 entered promiscuous mode [ 111.781085] bridge0: port 2(bridge_slave_1) entered blocking state [ 111.787453] bridge0: port 2(bridge_slave_1) entered disabled state [ 111.794600] device bridge_slave_1 entered promiscuous mode [ 111.810901] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 111.827755] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 111.872996] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 111.892218] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 111.961235] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 111.968541] team0: Port device team_slave_0 added [ 111.985282] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 111.992529] team0: Port device team_slave_1 added [ 112.009126] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 112.027753] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 112.046325] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 112.064455] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 112.195972] bridge0: port 2(bridge_slave_1) entered blocking state [ 112.202437] bridge0: port 2(bridge_slave_1) entered forwarding state [ 112.209396] bridge0: port 1(bridge_slave_0) entered blocking state [ 112.215781] bridge0: port 1(bridge_slave_0) entered forwarding state [ 112.692341] 8021q: adding VLAN 0 to HW filter on device bond0 [ 112.739377] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 112.787481] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 112.793721] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 112.801228] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 112.846151] 8021q: adding VLAN 0 to HW filter on device team0 [ 113.149393] [ 113.151100] ====================================================== [ 113.157399] WARNING: possible circular locking dependency detected [ 113.163700] 4.19.0-rc1+ #195 Not tainted [ 113.167747] ------------------------------------------------------ [ 113.174054] syz-executor0/4934 is trying to acquire lock: [ 113.179647] 00000000b04adc1c ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 113.188921] [ 113.188921] but task is already holding lock: [ 113.194873] 0000000098ef9bd4 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 113.202587] [ 113.202587] which lock already depends on the new lock. [ 113.202587] [ 113.211059] [ 113.211059] the existing dependency chain (in reverse order) is: [ 113.218668] [ 113.218668] -> #2 (rtnl_mutex){+.+.}: [ 113.223947] __mutex_lock+0x171/0x1700 [ 113.228348] mutex_lock_nested+0x16/0x20 [ 113.232914] rtnl_lock+0x17/0x20 [ 113.236787] bond_netdev_notify_work+0x44/0xd0 [ 113.241874] process_one_work+0xc73/0x1aa0 [ 113.246627] worker_thread+0x189/0x13c0 [ 113.251115] kthread+0x35a/0x420 [ 113.254987] ret_from_fork+0x3a/0x50 [ 113.259199] [ 113.259199] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 113.266909] process_one_work+0xc0b/0x1aa0 [ 113.271652] worker_thread+0x189/0x13c0 [ 113.276132] kthread+0x35a/0x420 [ 113.280006] ret_from_fork+0x3a/0x50 [ 113.284222] [ 113.284222] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 113.291315] lock_acquire+0x1e4/0x4f0 [ 113.295630] flush_workqueue+0x30a/0x1e10 [ 113.300293] drain_workqueue+0x2a9/0x640 [ 113.304864] destroy_workqueue+0xc6/0x9d0 [ 113.309521] __alloc_workqueue_key+0xef9/0x1190 [ 113.314694] bond_init+0x269/0x940 [ 113.318741] register_netdevice+0x337/0x1100 [ 113.323653] bond_newlink+0x49/0xa0 [ 113.327786] rtnl_newlink+0xef4/0x1d50 [ 113.332174] rtnetlink_rcv_msg+0x46e/0xc30 [ 113.336912] netlink_rcv_skb+0x172/0x440 [ 113.341472] rtnetlink_rcv+0x1c/0x20 [ 113.345685] netlink_unicast+0x5a0/0x760 [ 113.350247] netlink_sendmsg+0xa18/0xfc0 [ 113.354810] sock_sendmsg+0xd5/0x120 [ 113.359030] ___sys_sendmsg+0x7fd/0x930 [ 113.363507] __sys_sendmsg+0x11d/0x290 [ 113.367898] __x64_sys_sendmsg+0x78/0xb0 [ 113.372461] do_syscall_64+0x1b9/0x820 [ 113.376851] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 113.382603] [ 113.382603] other info that might help us debug this: [ 113.382603] [ 113.390749] Chain exists of: [ 113.390749] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 113.390749] [ 113.404447] Possible unsafe locking scenario: [ 113.404447] [ 113.410496] CPU0 CPU1 [ 113.415150] ---- ---- [ 113.419795] lock(rtnl_mutex); [ 113.423056] lock((work_completion)(&(&nnw->work)->work)); [ 113.431264] lock(rtnl_mutex); [ 113.437048] lock((wq_completion)bond_dev->name); [ 113.441958] [ 113.441958] *** DEADLOCK *** [ 113.441958] [ 113.448118] 1 lock held by syz-executor0/4934: [ 113.452679] #0: 0000000098ef9bd4 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 113.460827] [ 113.460827] stack backtrace: [ 113.465306] CPU: 1 PID: 4934 Comm: syz-executor0 Not tainted 4.19.0-rc1+ #195 [ 113.472676] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 113.482089] Call Trace: [ 113.484685] dump_stack+0x1c9/0x2b4 [ 113.488307] ? dump_stack_print_info.cold.2+0x52/0x52 [ 113.493492] ? vprintk_func+0x81/0x117 [ 113.497367] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 113.503073] ? save_trace+0xe0/0x290 [ 113.506774] __lock_acquire+0x3449/0x5020 [ 113.510905] ? mark_held_locks+0x160/0x160 [ 113.515128] ? __lock_is_held+0xb5/0x140 [ 113.519174] ? update_curr+0x344/0xba0 [ 113.523054] ? __account_cfs_rq_runtime+0x770/0x770 [ 113.528066] ? mark_held_locks+0x160/0x160 [ 113.532287] ? lock_downgrade+0x8f0/0x8f0 [ 113.536419] lock_acquire+0x1e4/0x4f0 [ 113.540209] ? flush_workqueue+0x2db/0x1e10 [ 113.544519] ? lock_release+0x9f0/0x9f0 [ 113.548482] ? lockdep_init_map+0x9/0x10 [ 113.552531] ? __init_waitqueue_head+0x9e/0x150 [ 113.557189] ? init_wait_entry+0x1c0/0x1c0 [ 113.561411] flush_workqueue+0x30a/0x1e10 [ 113.565545] ? flush_workqueue+0x2db/0x1e10 [ 113.569867] ? lock_acquire+0x1e4/0x4f0 [ 113.573829] ? drain_workqueue+0xa9/0x640 [ 113.577979] ? lock_release+0x9f0/0x9f0 [ 113.581948] ? check_same_owner+0x340/0x340 [ 113.586261] ? __queue_delayed_work+0x390/0x390 [ 113.590912] ? graph_lock+0x170/0x170 [ 113.594701] ? kasan_check_write+0x14/0x20 [ 113.598918] ? __mutex_lock+0x6d0/0x1700 [ 113.602978] ? drain_workqueue+0xa9/0x640 [ 113.607222] ? graph_lock+0x170/0x170 [ 113.611005] ? print_usage_bug+0xc0/0xc0 [ 113.615060] ? find_held_lock+0x36/0x1c0 [ 113.619114] ? lock_downgrade+0x8f0/0x8f0 [ 113.623291] ? graph_lock+0x170/0x170 [ 113.627082] ? graph_lock+0x170/0x170 [ 113.630863] ? find_held_lock+0x36/0x1c0 [ 113.634909] ? kasan_check_write+0x14/0x20 [ 113.639130] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 113.644044] ? wait_for_completion+0x8d0/0x8d0 [ 113.648658] ? do_raw_spin_unlock+0xa7/0x2f0 [ 113.653057] ? trace_hardirqs_on+0x2c0/0x2c0 [ 113.657454] drain_workqueue+0x2a9/0x640 [ 113.661500] ? drain_workqueue+0x2a9/0x640 [ 113.665720] ? flush_workqueue+0x1e10/0x1e10 [ 113.670114] ? save_stack+0xa9/0xd0 [ 113.673723] ? save_stack+0x43/0xd0 [ 113.677331] ? __kasan_slab_free+0x11a/0x170 [ 113.681722] ? kasan_slab_free+0xe/0x10 [ 113.685677] ? print_usage_bug+0xc0/0xc0 [ 113.689721] ? bond_init+0x269/0x940 [ 113.693417] ? register_netdevice+0x337/0x1100 [ 113.697999] ? bond_newlink+0x49/0xa0 [ 113.701782] ? rtnl_newlink+0xef4/0x1d50 [ 113.705832] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 113.710235] ? netlink_rcv_skb+0x172/0x440 [ 113.714453] ? rtnetlink_rcv+0x1c/0x20 [ 113.718320] ? netlink_unicast+0x5a0/0x760 [ 113.722537] ? netlink_sendmsg+0xa18/0xfc0 [ 113.726756] ? sock_sendmsg+0xd5/0x120 [ 113.730639] destroy_workqueue+0xc6/0x9d0 [ 113.734789] ? kasan_check_write+0x14/0x20 [ 113.739013] ? wq_watchdog_timer_fn+0x830/0x830 [ 113.743740] ? mark_held_locks+0xc9/0x160 [ 113.747884] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 113.753058] ? kfree+0x111/0x210 [ 113.756404] ? kfree+0x111/0x210 [ 113.759762] ? lockdep_hardirqs_on+0x421/0x5c0 [ 113.764330] ? trace_hardirqs_on+0xbd/0x2c0 [ 113.768643] ? init_rescuer.part.26+0x155/0x190 [ 113.773303] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 113.778391] ? __kasan_slab_free+0x131/0x170 [ 113.782783] ? init_rescuer.part.26+0x155/0x190 [ 113.787438] __alloc_workqueue_key+0xef9/0x1190 [ 113.792183] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 113.797707] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 113.802823] ? put_dec+0xf0/0xf0 [ 113.806221] ? format_decode+0x1b1/0xaf0 [ 113.810275] ? set_precision+0xe0/0xe0 [ 113.814148] ? simple_strtoll+0xa0/0xa0 [ 113.818110] ? graph_lock+0x170/0x170 [ 113.821942] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 113.827485] ? vsnprintf+0x20d/0x1b60 [ 113.831269] ? find_held_lock+0x36/0x1c0 [ 113.835313] ? lock_downgrade+0x8f0/0x8f0 [ 113.839449] ? kasan_check_read+0x11/0x20 [ 113.843583] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 113.848243] bond_init+0x269/0x940 [ 113.851776] ? __dev_get_by_name+0x170/0x170 [ 113.856168] ? bond_arp_rcv+0x11c0/0x11c0 [ 113.860297] ? check_same_owner+0x340/0x340 [ 113.864605] ? rcu_note_context_switch+0x680/0x680 [ 113.869535] ? bond_arp_rcv+0x11c0/0x11c0 [ 113.873671] register_netdevice+0x337/0x1100 [ 113.878065] ? netdev_change_features+0x110/0x110 [ 113.882947] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 113.888484] ? ns_capable_common+0x13f/0x170 [ 113.892872] ? ns_capable+0x22/0x30 [ 113.896551] bond_newlink+0x49/0xa0 [ 113.900171] ? bond_changelink+0x2360/0x2360 [ 113.904564] rtnl_newlink+0xef4/0x1d50 [ 113.908440] ? rtnl_link_unregister+0x390/0x390 [ 113.913093] ? print_usage_bug+0xc0/0xc0 [ 113.917141] ? __lock_acquire+0x7fc/0x5020 [ 113.921360] ? print_usage_bug+0xc0/0xc0 [ 113.925405] ? graph_lock+0x170/0x170 [ 113.929190] ? print_usage_bug+0xc0/0xc0 [ 113.933233] ? mark_held_locks+0x160/0x160 [ 113.937452] ? __lock_acquire+0x7fc/0x5020 [ 113.941674] ? lock_acquire+0x1e4/0x4f0 [ 113.945640] ? rtnetlink_rcv_msg+0x412/0xc30 [ 113.950045] ? lock_release+0x9f0/0x9f0 [ 113.954006] ? check_same_owner+0x340/0x340 [ 113.958317] ? mutex_trylock+0x2b0/0x2b0 [ 113.962362] ? __lock_acquire+0x7fc/0x5020 [ 113.966584] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 113.972117] ? refcount_sub_and_test_checked+0x21a/0x350 [ 113.977559] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 113.983089] ? rtnl_get_link+0x170/0x370 [ 113.987146] ? rtnl_dump_all+0x600/0x600 [ 113.991234] ? rcu_is_watching+0x8c/0x150 [ 113.995378] ? rtnl_link_unregister+0x390/0x390 [ 114.000119] rtnetlink_rcv_msg+0x46e/0xc30 [ 114.004340] ? rtnetlink_put_metrics+0x690/0x690 [ 114.009083] netlink_rcv_skb+0x172/0x440 [ 114.013130] ? rtnetlink_put_metrics+0x690/0x690 [ 114.017866] ? netlink_ack+0xbe0/0xbe0 [ 114.021738] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 114.026389] rtnetlink_rcv+0x1c/0x20 [ 114.030085] netlink_unicast+0x5a0/0x760 [ 114.034129] ? netlink_attachskb+0x9a0/0x9a0 [ 114.038527] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 114.044047] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 114.049045] netlink_sendmsg+0xa18/0xfc0 [ 114.053088] ? netlink_unicast+0x760/0x760 [ 114.057310] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 114.062222] ? apparmor_socket_sendmsg+0x29/0x30 [ 114.066972] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 114.072493] ? security_socket_sendmsg+0x94/0xc0 [ 114.077239] ? netlink_unicast+0x760/0x760 [ 114.081458] sock_sendmsg+0xd5/0x120 [ 114.085171] ___sys_sendmsg+0x7fd/0x930 [ 114.089132] ? copy_msghdr_from_user+0x580/0x580 [ 114.093872] ? lock_downgrade+0x8f0/0x8f0 [ 114.098008] ? __fget_light+0x2f7/0x440 [ 114.101975] ? fget_raw+0x20/0x20 [ 114.105414] ? __fd_install+0x2db/0x880 [ 114.109370] ? get_unused_fd_flags+0x1a0/0x1a0 [ 114.113936] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 114.119469] ? sockfd_lookup_light+0xc5/0x160 [ 114.123946] __sys_sendmsg+0x11d/0x290 [ 114.127824] ? __ia32_sys_shutdown+0x80/0x80 [ 114.132217] ? __x64_sys_futex+0x47f/0x6a0 [ 114.136437] ? do_syscall_64+0x9a/0x820 [ 114.140395] ? do_syscall_64+0x9a/0x820 [ 114.144360] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 114.149445] ? trace_hardirqs_off+0xb8/0x2b0 [ 114.153840] __x64_sys_sendmsg+0x78/0xb0 [ 114.157883] do_syscall_64+0x1b9/0x820 [ 114.161753] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 114.167116] ? syscall_return_slowpath+0x5e0/0x5e0 [ 114.172031] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 114.177041] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 114.182042] ? recalc_sigpending_tsk+0x180/0x180 [ 114.186781] ? kasan_check_write+0x14/0x20 [ 114.191000] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 114.195831] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 114.201001] RIP: 0033:0x457099 [ 114.204179] 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 [ 114.223061] RSP: 002b:00007f6b5b80ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 114.230751] RAX: ffffffffffffffda RBX: 00007f6b5b80f6d4 RCX: 0000000000457099 [ 114.238000] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 114.245252] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 114.252506] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 114.259763] R13: 00000000004d4890 R14: 00000000004c8ee5 R15: 0000000000000000 2018/08/31 23:28:14 executed programs: 120 2018/08/31 23:28:19 executed programs: 377