[ OK ] Started Getty on tty2. [ OK ] Started Getty on tty1. [ OK ] Started Serial Getty on ttyS0. [ OK ] Reached target Login Prompts. [ OK ] Reached target Multi-User System. [ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... [ OK ] Started Update UTMP about System Runlevel Changes. Starting Load/Save RF Kill Switch Status... [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.0.93' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 29.731394] xt_CT: netfilter: NOTRACK target is deprecated, use CT instead or upgrade iptables [ 29.741316] ip_tables: iptables: counters copy to user failed while replacing table [ 29.752648] IPVS: ftp: loaded support on port[0] = 21 executing program [ 29.786406] ip_tables: iptables: counters copy to user failed while replacing table [ 29.797109] IPVS: ftp: loaded support on port[0] = 21 [ 29.842331] ip_tables: iptables: counters copy to user failed while replacing table [ 29.892377] [ 29.894133] ====================================================== [ 29.900434] WARNING: possible circular locking dependency detected [ 29.906785] 4.14.226-syzkaller #0 Not tainted [ 29.911262] ------------------------------------------------------ [ 29.917582] kworker/u4:5/3544 is trying to acquire lock: [ 29.923041] (&table[i].mutex){+.+.}, at: [] nf_tables_netdev_event+0x10d/0x4d0 [ 29.932087] [ 29.932087] but task is already holding lock: [ 29.938055] (rtnl_mutex){+.+.}, at: [] ip6gre_exit_net+0x70/0x570 [ 29.945952] [ 29.945952] which lock already depends on the new lock. [ 29.945952] [ 29.954250] [ 29.954250] the existing dependency chain (in reverse order) is: [ 29.961854] [ 29.961854] -> #2 (rtnl_mutex){+.+.}: [ 29.967136] __mutex_lock+0xc4/0x1310 [ 29.971441] unregister_netdevice_notifier+0x5e/0x2b0 [ 29.977794] tee_tg_destroy+0x5c/0xb0 [ 29.982100] cleanup_entry+0x1fd/0x2d0 [ 29.986493] __do_replace+0x38d/0x570 [ 29.990816] do_ipt_set_ctl+0x256/0x3a0 [ 29.995300] nf_setsockopt+0x5f/0xb0 [ 29.999542] ip_setsockopt+0x94/0xb0 [ 30.003767] udp_setsockopt+0x45/0x80 [ 30.008080] SyS_setsockopt+0x110/0x1e0 [ 30.012570] do_syscall_64+0x1d5/0x640 [ 30.017053] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.022737] [ 30.022737] -> #1 (&xt[i].mutex){+.+.}: [ 30.028204] __mutex_lock+0xc4/0x1310 [ 30.032534] target_revfn+0x43/0x210 [ 30.036929] xt_find_revision+0x15e/0x1d0 [ 30.041601] nfnl_compat_get+0x1f7/0x870 [ 30.046457] nfnetlink_rcv_msg+0x9bb/0xc00 [ 30.051233] netlink_rcv_skb+0x125/0x390 [ 30.055826] nfnetlink_rcv+0x1ab/0x1da0 [ 30.060331] netlink_unicast+0x437/0x610 [ 30.064896] netlink_sendmsg+0x62e/0xb80 [ 30.069563] sock_sendmsg+0xb5/0x100 [ 30.073932] ___sys_sendmsg+0x6c8/0x800 [ 30.078408] __sys_sendmsg+0xa3/0x120 [ 30.082732] SyS_sendmsg+0x27/0x40 [ 30.086787] do_syscall_64+0x1d5/0x640 [ 30.094671] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 30.100366] [ 30.100366] -> #0 (&table[i].mutex){+.+.}: [ 30.106190] lock_acquire+0x170/0x3f0 [ 30.110499] __mutex_lock+0xc4/0x1310 [ 30.114803] nf_tables_netdev_event+0x10d/0x4d0 [ 30.120001] notifier_call_chain+0x108/0x1a0 [ 30.125040] rollback_registered_many+0x765/0xba0 [ 30.130848] unregister_netdevice_many.part.0+0x18/0x2e0 [ 30.136821] unregister_netdevice_many+0x36/0x50 [ 30.142095] ip6gre_exit_net+0x41e/0x570 [ 30.146842] ops_exit_list+0xa5/0x150 [ 30.151150] cleanup_net+0x3b3/0x840 [ 30.155392] process_one_work+0x793/0x14a0 [ 30.160351] worker_thread+0x5cc/0xff0 [ 30.164760] kthread+0x30d/0x420 [ 30.168635] ret_from_fork+0x24/0x30 [ 30.172860] [ 30.172860] other info that might help us debug this: [ 30.172860] [ 30.181082] Chain exists of: [ 30.181082] &table[i].mutex --> &xt[i].mutex --> rtnl_mutex [ 30.181082] [ 30.191314] Possible unsafe locking scenario: [ 30.191314] [ 30.197352] CPU0 CPU1 [ 30.202015] ---- ---- [ 30.206674] lock(rtnl_mutex); [ 30.209939] lock(&xt[i].mutex); [ 30.215905] lock(rtnl_mutex); [ 30.221681] lock(&table[i].mutex); [ 30.225378] [ 30.225378] *** DEADLOCK *** [ 30.225378] [ 30.231432] 4 locks held by kworker/u4:5/3544: [ 30.236000] #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 [ 30.244666] #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 [ 30.253756] #2: (net_mutex){+.+.}, at: [] cleanup_net+0x110/0x840 [ 30.261885] #3: (rtnl_mutex){+.+.}, at: [] ip6gre_exit_net+0x70/0x570 [ 30.270224] [ 30.270224] stack backtrace: [ 30.274708] CPU: 0 PID: 3544 Comm: kworker/u4:5 Not tainted 4.14.226-syzkaller #0 [ 30.282388] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.291750] Workqueue: netns cleanup_net [ 30.295807] Call Trace: [ 30.298391] dump_stack+0x1b2/0x281 [ 30.302014] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 30.307806] __lock_acquire+0x2e0e/0x3f20 [ 30.311950] ? unwind_next_frame+0x404/0x17d0 [ 30.316441] ? trace_hardirqs_on+0x10/0x10 [ 30.320669] ? check_usage_forwards+0x2d0/0x2d0 [ 30.325351] ? ret_from_fork+0x24/0x30 [ 30.329249] lock_acquire+0x170/0x3f0 [ 30.333054] ? nf_tables_netdev_event+0x10d/0x4d0 [ 30.337995] ? nf_tables_netdev_event+0x10d/0x4d0 [ 30.342929] __mutex_lock+0xc4/0x1310 [ 30.346720] ? nf_tables_netdev_event+0x10d/0x4d0 [ 30.351634] ? nf_tables_netdev_event+0x10d/0x4d0 [ 30.356467] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 30.361929] ? trace_hardirqs_on+0x10/0x10 [ 30.366186] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 30.371186] ? lock_downgrade+0x740/0x740 [ 30.375334] nf_tables_netdev_event+0x10d/0x4d0 [ 30.379996] ? mirred_device_event+0x12f/0x170 [ 30.384585] ? nf_tables_netdev_init_net+0x140/0x140 [ 30.389669] ? mirred_device_event+0x12f/0x170 [ 30.394231] ? __local_bh_enable_ip+0xc1/0x170 [ 30.398818] notifier_call_chain+0x108/0x1a0 [ 30.403230] rollback_registered_many+0x765/0xba0 [ 30.408155] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 30.413892] ? netdev_state_change+0xf0/0xf0 [ 30.418323] ? lock_acquire+0x170/0x3f0 [ 30.422286] unregister_netdevice_many.part.0+0x18/0x2e0 [ 30.427912] unregister_netdevice_many+0x36/0x50 [ 30.432671] ip6gre_exit_net+0x41e/0x570 [ 30.436723] ? lock_downgrade+0x740/0x740 [ 30.440859] ? ip6gre_dellink+0x260/0x260 [ 30.445112] ? ip6gre_dellink+0x260/0x260 [ 30.449247] ops_exit_list+0xa5/0x150 [ 30.453035] cleanup_net+0x3b3/0x840 [ 30.456758] ? net_drop_ns+0x70/0x70 [ 30.460459] ? lock_acquire+0x170/0x3f0 [ 30.464436] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 30.469979] process_one_work+0x793/0x14a0 [ 30.474226] ? work_busy+0x320/0x320 [ 30.477919] ? worker_thread+0x158/0xff0 [ 30.482086] ? _raw_spin_unlock_irq+0x24/0x80 [ 30.486564] worker_thread+0x5cc/0xff0 [ 30.490448] ? rescuer_thread+0xc80/0xc80 [ 30.494703] kthread+0x30d/0x420 [ 30.498053] ? kthread_create_on_node+0xd0/0xd0 [ 30.502711] ret_from_fork+0x24/0x30 executing program executing program [ 31.100907] IPVS: ftp: loaded support on port[0] = 21 [ 31.130455] ip_tables: iptables: counters copy to user failed while replacing table [ 31.140998] IPVS: ftp: loaded support on port[0] = 21 [ 31.170973] ip_tables: iptables: counters copy to user failed while replacing table executing program executing program [ 31.890543] IPVS: ftp: loaded support on port[0] = 21 [ 31.919338] ip_tables: iptables: counters copy to user failed while replacing table [ 31.930208] IPVS: ftp: loaded support on port[0] = 21 [ 31.970620] ip_tables: iptables: counters copy to user failed while replacing table executing program [ 33.076215] IPVS: ftp: loaded support on port[0] = 21 executing program [ 33.105461] ip_tables: iptables: counters copy to user failed while replacing table [ 33.116126] IPVS: ftp: loaded support on port[0] = 21 [ 33.147198] ip_tables: iptables: counters copy to user failed while replacing table executing program [ 34.255973] IPVS: ftp: loaded support on port[0] = 21 [ 34.284355] ip_tables: iptables: counters copy to user failed while replacing table executing program [ 35.404891] IPVS: ftp: loaded support on port[0] = 21 [ 35.437901] ip_tables: iptables: counters copy to user failed while replacing table executing program executing program [ 36.088901] IPVS: ftp: loaded support on port[0] = 21 [ 36.117189] ip_tables: iptables: counters copy to user failed while replacing table [ 36.128443] IPVS: ftp: loaded support on port[0] = 21 [ 36.158905] ip_tables: iptables: counters copy to user failed while replacing table executing program [ 36.767354] IPVS: ftp: loaded support on port[0] = 21 [ 36.796177] ip_tables: iptables: counters copy to user failed while replacing table [ 36.806500] IPVS: ftp: loaded support on port[0] = 21 executing program [ 36.837508] ip_tables: iptables: counters copy to user failed while replacing table executing program [ 37.933620] IPVS: ftp: loaded support on port[0] = 21 [ 37.962310] ip_tables: iptables: counters copy to user failed while replacing table executing program [ 39.124049] IPVS: ftp: loaded support on port[0] = 21 [ 39.153542] ip_tables: iptables: counters copy to user failed while replacing table executing program executing program [ 39.816491] IPVS: ftp: loaded support on port[0] = 21 [ 39.845135] ip_tables: iptables: counters copy to user failed while replacing table [ 39.856147] IPVS: ftp: loaded support on port[0] = 21