[....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[ 18.746172] random: sshd: uninitialized urandom read (32 bytes read) [?25l[?1c7[ ok 8[?25h[?0c. [ 19.722315] random: sshd: uninitialized urandom read (32 bytes read) Debian GNU/Linux 7 syzkaller ttyS0 syzkaller login: [ 20.065072] random: sshd: uninitialized urandom read (32 bytes read) [ 20.588191] random: sshd: uninitialized urandom read (32 bytes read) [ 20.764505] random: sshd: uninitialized urandom read (32 bytes read) Warning: Permanently added '10.128.10.48' (ECDSA) to the list of known hosts. [ 26.427503] random: sshd: uninitialized urandom read (32 bytes read) 2018/09/11 23:01:03 parsed 1 programs [ 27.641839] random: cc1: uninitialized urandom read (8 bytes read) 2018/09/11 23:01:04 executed programs: 0 [ 28.726935] IPVS: ftp: loaded support on port[0] = 21 [ 28.938230] bridge0: port 1(bridge_slave_0) entered blocking state [ 28.944819] bridge0: port 1(bridge_slave_0) entered disabled state [ 28.952462] device bridge_slave_0 entered promiscuous mode [ 28.969576] bridge0: port 2(bridge_slave_1) entered blocking state [ 28.975967] bridge0: port 2(bridge_slave_1) entered disabled state [ 28.983248] device bridge_slave_1 entered promiscuous mode [ 29.000325] IPv6: ADDRCONF(NETDEV_UP): veth0_to_bridge: link is not ready [ 29.016903] IPv6: ADDRCONF(NETDEV_UP): veth1_to_bridge: link is not ready [ 29.061926] bond0: Enslaving bond_slave_0 as an active interface with an up link [ 29.081403] bond0: Enslaving bond_slave_1 as an active interface with an up link [ 29.148003] IPv6: ADDRCONF(NETDEV_UP): team_slave_0: link is not ready [ 29.155308] team0: Port device team_slave_0 added [ 29.170971] IPv6: ADDRCONF(NETDEV_UP): team_slave_1: link is not ready [ 29.178117] team0: Port device team_slave_1 added [ 29.194512] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_0: link becomes ready [ 29.213924] IPv6: ADDRCONF(NETDEV_CHANGE): team_slave_1: link becomes ready [ 29.231692] IPv6: ADDRCONF(NETDEV_CHANGE): veth0_to_bridge: link becomes ready [ 29.249568] IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready [ 29.375003] bridge0: port 2(bridge_slave_1) entered blocking state [ 29.381470] bridge0: port 2(bridge_slave_1) entered forwarding state [ 29.388530] bridge0: port 1(bridge_slave_0) entered blocking state [ 29.394956] bridge0: port 1(bridge_slave_0) entered forwarding state [ 29.848626] IPv6: ADDRCONF(NETDEV_UP): bond0: link is not ready [ 29.854766] 8021q: adding VLAN 0 to HW filter on device bond0 [ 29.899986] IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready [ 29.909961] IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready [ 29.958926] IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready [ 29.965452] IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready [ 29.972954] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready [ 30.017093] 8021q: adding VLAN 0 to HW filter on device team0 [ 30.314260] [ 30.315942] ====================================================== [ 30.322240] WARNING: possible circular locking dependency detected [ 30.328548] 4.19.0-rc2-next-20180904+ #55 Not tainted [ 30.333718] ------------------------------------------------------ [ 30.340018] syz-executor0/4520 is trying to acquire lock: [ 30.345536] 00000000c72688d9 ((wq_completion)bond_dev->name){+.+.}, at: flush_workqueue+0x2db/0x1e10 [ 30.354812] [ 30.354812] but task is already holding lock: [ 30.360769] 00000000a30329a6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 30.368480] [ 30.368480] which lock already depends on the new lock. [ 30.368480] [ 30.376786] [ 30.376786] the existing dependency chain (in reverse order) is: [ 30.384395] [ 30.384395] -> #2 (rtnl_mutex){+.+.}: [ 30.389685] __mutex_lock+0x171/0x1700 [ 30.394079] mutex_lock_nested+0x16/0x20 [ 30.398647] rtnl_lock+0x17/0x20 [ 30.402520] bond_netdev_notify_work+0x44/0xd0 [ 30.407608] process_one_work+0xc73/0x1aa0 [ 30.412360] worker_thread+0x189/0x13c0 [ 30.416850] kthread+0x35a/0x420 [ 30.420747] ret_from_fork+0x3a/0x50 [ 30.424991] [ 30.424991] -> #1 ((work_completion)(&(&nnw->work)->work)){+.+.}: [ 30.432700] process_one_work+0xc0b/0x1aa0 [ 30.437443] worker_thread+0x189/0x13c0 [ 30.441921] kthread+0x35a/0x420 [ 30.445794] ret_from_fork+0x3a/0x50 [ 30.450006] [ 30.450006] -> #0 ((wq_completion)bond_dev->name){+.+.}: [ 30.456951] lock_acquire+0x1e4/0x4f0 [ 30.461270] flush_workqueue+0x30a/0x1e10 [ 30.465929] drain_workqueue+0x2a9/0x640 [ 30.470517] destroy_workqueue+0xc6/0x9d0 [ 30.475171] __alloc_workqueue_key+0xef9/0x1190 [ 30.480354] bond_init+0x269/0x940 [ 30.484421] register_netdevice+0x337/0x1100 [ 30.489344] bond_newlink+0x49/0xa0 [ 30.493486] rtnl_newlink+0xef4/0x1d50 [ 30.497879] rtnetlink_rcv_msg+0x46e/0xc30 [ 30.502619] netlink_rcv_skb+0x172/0x440 [ 30.507185] rtnetlink_rcv+0x1c/0x20 [ 30.511422] netlink_unicast+0x5a0/0x760 [ 30.515989] netlink_sendmsg+0xa18/0xfc0 [ 30.520552] sock_sendmsg+0xd5/0x120 [ 30.524773] ___sys_sendmsg+0x7fd/0x930 [ 30.529248] __sys_sendmsg+0x11d/0x290 [ 30.533640] __x64_sys_sendmsg+0x78/0xb0 [ 30.538211] do_syscall_64+0x1b9/0x820 [ 30.542640] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 30.548328] [ 30.548328] other info that might help us debug this: [ 30.548328] [ 30.556486] Chain exists of: [ 30.556486] (wq_completion)bond_dev->name --> (work_completion)(&(&nnw->work)->work) --> rtnl_mutex [ 30.556486] [ 30.570185] Possible unsafe locking scenario: [ 30.570185] [ 30.576224] CPU0 CPU1 [ 30.580869] ---- ---- [ 30.585521] lock(rtnl_mutex); [ 30.588783] lock((work_completion)(&(&nnw->work)->work)); [ 30.596992] lock(rtnl_mutex); [ 30.602769] lock((wq_completion)bond_dev->name); [ 30.607685] [ 30.607685] *** DEADLOCK *** [ 30.607685] [ 30.613737] 1 lock held by syz-executor0/4520: [ 30.618316] #0: 00000000a30329a6 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x412/0xc30 [ 30.626479] [ 30.626479] stack backtrace: [ 30.630962] CPU: 0 PID: 4520 Comm: syz-executor0 Not tainted 4.19.0-rc2-next-20180904+ #55 [ 30.639353] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.648719] Call Trace: [ 30.651323] dump_stack+0x1c9/0x2b4 [ 30.654951] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.660130] ? vprintk_func+0x81/0x117 [ 30.664001] print_circular_bug.isra.34.cold.55+0x1bd/0x27d [ 30.669718] ? save_trace+0xe0/0x290 [ 30.673426] __lock_acquire+0x3449/0x5020 [ 30.677570] ? mark_held_locks+0x160/0x160 [ 30.681883] ? __lock_is_held+0xb5/0x140 [ 30.685934] ? update_curr+0x344/0xba0 [ 30.689834] ? __account_cfs_rq_runtime+0x770/0x770 [ 30.694852] ? mark_held_locks+0x160/0x160 [ 30.699073] ? lock_downgrade+0x8f0/0x8f0 [ 30.703221] lock_acquire+0x1e4/0x4f0 [ 30.707010] ? flush_workqueue+0x2db/0x1e10 [ 30.711315] ? lock_release+0x9f0/0x9f0 [ 30.715272] ? lockdep_init_map+0x9/0x10 [ 30.719319] ? __init_waitqueue_head+0x9e/0x150 [ 30.723972] ? init_wait_entry+0x1c0/0x1c0 [ 30.728193] flush_workqueue+0x30a/0x1e10 [ 30.732335] ? flush_workqueue+0x2db/0x1e10 [ 30.736666] ? lock_acquire+0x1e4/0x4f0 [ 30.740636] ? drain_workqueue+0xa9/0x640 [ 30.744789] ? lock_release+0x9f0/0x9f0 [ 30.748764] ? check_same_owner+0x340/0x340 [ 30.753080] ? __queue_delayed_work+0x390/0x390 [ 30.757742] ? graph_lock+0x170/0x170 [ 30.761528] ? kasan_check_write+0x14/0x20 [ 30.765747] ? __mutex_lock+0x6d0/0x1700 [ 30.769877] ? drain_workqueue+0xa9/0x640 [ 30.774008] ? graph_lock+0x170/0x170 [ 30.777794] ? print_usage_bug+0xc0/0xc0 [ 30.781839] ? find_held_lock+0x36/0x1c0 [ 30.785888] ? lock_downgrade+0x8f0/0x8f0 [ 30.790018] ? graph_lock+0x170/0x170 [ 30.793800] ? graph_lock+0x170/0x170 [ 30.797690] ? find_held_lock+0x36/0x1c0 [ 30.801740] ? kasan_check_write+0x14/0x20 [ 30.805958] ? __mutex_unlock_slowpath+0x197/0x8c0 [ 30.810871] ? wait_for_completion+0x8d0/0x8d0 [ 30.815449] ? do_raw_spin_unlock+0xa7/0x2f0 [ 30.819845] ? trace_hardirqs_on+0x2c0/0x2c0 [ 30.824240] drain_workqueue+0x2a9/0x640 [ 30.828286] ? drain_workqueue+0x2a9/0x640 [ 30.832528] ? flush_workqueue+0x1e10/0x1e10 [ 30.836924] ? save_stack+0xa9/0xd0 [ 30.840536] ? save_stack+0x43/0xd0 [ 30.844148] ? __kasan_slab_free+0x11a/0x170 [ 30.848541] ? kasan_slab_free+0xe/0x10 [ 30.852509] ? print_usage_bug+0xc0/0xc0 [ 30.856592] ? bond_init+0x269/0x940 [ 30.860311] ? register_netdevice+0x337/0x1100 [ 30.864878] ? bond_newlink+0x49/0xa0 [ 30.868663] ? rtnl_newlink+0xef4/0x1d50 [ 30.872711] ? rtnetlink_rcv_msg+0x46e/0xc30 [ 30.877105] ? netlink_rcv_skb+0x172/0x440 [ 30.881328] ? rtnetlink_rcv+0x1c/0x20 [ 30.885204] ? netlink_unicast+0x5a0/0x760 [ 30.889430] ? netlink_sendmsg+0xa18/0xfc0 [ 30.893657] ? sock_sendmsg+0xd5/0x120 [ 30.897533] destroy_workqueue+0xc6/0x9d0 [ 30.901697] ? kasan_check_write+0x14/0x20 [ 30.905920] ? wq_watchdog_timer_fn+0x830/0x830 [ 30.910609] ? mark_held_locks+0xc9/0x160 [ 30.914746] ? _raw_spin_unlock_irqrestore+0x63/0xc0 [ 30.919835] ? kfree+0x111/0x210 [ 30.923185] ? kfree+0x111/0x210 [ 30.926543] ? lockdep_hardirqs_on+0x421/0x5c0 [ 30.931129] ? trace_hardirqs_on+0xbd/0x2c0 [ 30.935451] ? init_rescuer.part.26+0x155/0x190 [ 30.940108] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 30.945199] ? __kasan_slab_free+0x131/0x170 [ 30.949596] ? init_rescuer.part.26+0x155/0x190 [ 30.954254] __alloc_workqueue_key+0xef9/0x1190 [ 30.958917] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.964449] ? workqueue_sysfs_register+0x3f0/0x3f0 [ 30.969455] ? put_dec+0xf0/0xf0 [ 30.972808] ? format_decode+0x1b1/0xaf0 [ 30.976855] ? set_precision+0xe0/0xe0 [ 30.980749] ? simple_strtoll+0xa0/0xa0 [ 30.984730] ? graph_lock+0x170/0x170 [ 30.988582] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 30.994109] ? vsnprintf+0x20d/0x1b60 [ 30.997912] ? find_held_lock+0x36/0x1c0 [ 31.001964] ? lock_downgrade+0x8f0/0x8f0 [ 31.006121] ? kasan_check_read+0x11/0x20 [ 31.010276] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 31.014936] bond_init+0x269/0x940 [ 31.018504] ? __dev_get_by_name+0x170/0x170 [ 31.022900] ? bond_arp_rcv+0x11c0/0x11c0 [ 31.027045] ? check_same_owner+0x340/0x340 [ 31.031394] ? rcu_note_context_switch+0x680/0x680 [ 31.036334] ? bond_arp_rcv+0x11c0/0x11c0 [ 31.040482] register_netdevice+0x337/0x1100 [ 31.045266] ? netdev_change_features+0x110/0x110 [ 31.050126] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.055654] ? ns_capable_common+0x13f/0x170 [ 31.060075] bond_newlink+0x49/0xa0 [ 31.063711] ? bond_changelink+0x2360/0x2360 [ 31.068105] rtnl_newlink+0xef4/0x1d50 [ 31.072156] ? rtnl_link_unregister+0x390/0x390 [ 31.076814] ? print_usage_bug+0xc0/0xc0 [ 31.080863] ? __lock_acquire+0x7fc/0x5020 [ 31.085090] ? print_usage_bug+0xc0/0xc0 [ 31.089134] ? graph_lock+0x170/0x170 [ 31.092918] ? print_usage_bug+0xc0/0xc0 [ 31.096987] ? mark_held_locks+0x160/0x160 [ 31.101237] ? __lock_acquire+0x7fc/0x5020 [ 31.105460] ? lock_acquire+0x1e4/0x4f0 [ 31.109431] ? rtnetlink_rcv_msg+0x412/0xc30 [ 31.113846] ? lock_release+0x9f0/0x9f0 [ 31.117831] ? check_same_owner+0x340/0x340 [ 31.122154] ? mutex_trylock+0x2b0/0x2b0 [ 31.126296] ? __lock_acquire+0x7fc/0x5020 [ 31.130522] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.136050] ? refcount_sub_and_test_checked+0x21a/0x350 [ 31.141500] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 31.147026] ? rtnl_get_link+0x170/0x370 [ 31.151076] ? rtnl_dump_all+0x600/0x600 [ 31.155147] ? rcu_is_watching+0x8c/0x150 [ 31.159286] ? rtnl_link_unregister+0x390/0x390 [ 31.163944] rtnetlink_rcv_msg+0x46e/0xc30 [ 31.168200] ? rtnetlink_put_metrics+0x690/0x690 [ 31.172950] netlink_rcv_skb+0x172/0x440 [ 31.177003] ? rtnetlink_put_metrics+0x690/0x690 [ 31.181748] ? netlink_ack+0xbe0/0xbe0 [ 31.185625] ? rcu_cleanup_dead_rnp+0x200/0x200 [ 31.190287] rtnetlink_rcv+0x1c/0x20 [ 31.193992] netlink_unicast+0x5a0/0x760 [ 31.198044] ? netlink_attachskb+0x9a0/0x9a0 [ 31.202450] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.207980] ? __sanitizer_cov_trace_cmp4+0x16/0x20 [ 31.212992] netlink_sendmsg+0xa18/0xfc0 [ 31.217056] ? netlink_unicast+0x760/0x760 [ 31.221286] ? aa_sock_msg_perm.isra.13+0xba/0x160 [ 31.226204] ? apparmor_socket_sendmsg+0x29/0x30 [ 31.230951] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.236479] ? security_socket_sendmsg+0x94/0xc0 [ 31.241246] ? netlink_unicast+0x760/0x760 [ 31.245479] sock_sendmsg+0xd5/0x120 [ 31.249191] ___sys_sendmsg+0x7fd/0x930 [ 31.253152] ? copy_msghdr_from_user+0x580/0x580 [ 31.257895] ? lock_downgrade+0x8f0/0x8f0 [ 31.262031] ? __fget_light+0x2f7/0x440 [ 31.265989] ? fget_raw+0x20/0x20 [ 31.269434] ? __fd_install+0x2db/0x880 [ 31.273396] ? get_unused_fd_flags+0x1a0/0x1a0 [ 31.277977] ? __sanitizer_cov_trace_const_cmp8+0x18/0x20 [ 31.283500] ? sockfd_lookup_light+0xc5/0x160 [ 31.287983] __sys_sendmsg+0x11d/0x290 [ 31.291863] ? __ia32_sys_shutdown+0x80/0x80 [ 31.296259] ? __x64_sys_futex+0x47f/0x6a0 [ 31.300481] ? do_syscall_64+0x9a/0x820 [ 31.304462] ? do_syscall_64+0x9a/0x820 [ 31.308442] ? trace_hardirqs_off_caller+0x2b0/0x2b0 [ 31.313530] ? trace_hardirqs_off+0xb8/0x2b0 [ 31.317925] __x64_sys_sendmsg+0x78/0xb0 [ 31.321975] do_syscall_64+0x1b9/0x820 [ 31.325850] ? entry_SYSCALL_64_after_hwframe+0x3e/0xbe [ 31.331199] ? syscall_return_slowpath+0x5e0/0x5e0 [ 31.336115] ? trace_hardirqs_on_caller+0x2b0/0x2b0 [ 31.341135] ? prepare_exit_to_usermode+0x3b0/0x3b0 [ 31.346138] ? recalc_sigpending_tsk+0x180/0x180 [ 31.350880] ? kasan_check_write+0x14/0x20 [ 31.355103] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.359945] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.365126] RIP: 0033:0x4572d9 [ 31.368304] 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 [ 31.387203] RSP: 002b:00007f436cee5c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 31.394912] RAX: ffffffffffffffda RBX: 00007f436cee66d4 RCX: 00000000004572d9 [ 31.402166] RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000004 [ 31.409443] RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 [ 31.416723] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff [ 31.423975] R13: 00000000004d4eb0 R14: 00000000004c93f1 R15: 0000000000000000 2018/09/11 23:01:09 executed programs: 125 2018/09/11 23:01:14 executed programs: 386