[ 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. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.35' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 40.968819] audit: type=1400 audit(1596507993.466:8): avc: denied { execmem } for pid=6357 comm="syz-executor890" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1 [ 40.989762] ip6_tables: ip6tables: counters copy to user failed while replacing table [ 41.257430] IPVS: ftp: loaded support on port[0] = 21 executing program [ 42.339004] ip6_tables: ip6tables: counters copy to user failed while replacing table [ 42.686846] IPVS: ftp: loaded support on port[0] = 21 executing program [ 43.598766] ip6_tables: ip6tables: counters copy to user failed while replacing table [ 43.668160] [ 43.669800] ====================================================== [ 43.676093] WARNING: possible circular locking dependency detected [ 43.682392] 4.14.191-syzkaller #0 Not tainted [ 43.686856] ------------------------------------------------------ [ 43.693146] kworker/u4:3/110 is trying to acquire lock: [ 43.698480] (&table[i].mutex){+.+.}, at: [] nf_tables_netdev_event+0x10d/0x4d0 [ 43.707475] [ 43.707475] but task is already holding lock: [ 43.713415] (rtnl_mutex){+.+.}, at: [] ip6gre_exit_net+0x70/0x570 [ 43.721277] [ 43.721277] which lock already depends on the new lock. [ 43.721277] [ 43.729566] [ 43.729566] the existing dependency chain (in reverse order) is: [ 43.737184] [ 43.737184] -> #2 (rtnl_mutex){+.+.}: [ 43.742469] __mutex_lock+0xc4/0x1310 [ 43.746780] unregister_netdevice_notifier+0x5e/0x2b0 [ 43.752725] tee_tg_destroy+0x5c/0xb0 [ 43.757029] cleanup_entry+0x232/0x310 [ 43.761499] __do_replace+0x38d/0x580 [ 43.765795] do_ip6t_set_ctl+0x256/0x3a4 [ 43.770350] nf_setsockopt+0x5f/0xb0 [ 43.774577] ipv6_setsockopt+0xc0/0x120 [ 43.779044] tcp_setsockopt+0x7b/0xc0 [ 43.783361] SyS_setsockopt+0x110/0x1e0 [ 43.787845] do_syscall_64+0x1d5/0x640 [ 43.792228] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 43.797908] [ 43.797908] -> #1 (&xt[i].mutex){+.+.}: [ 43.803354] __mutex_lock+0xc4/0x1310 [ 43.807650] xt_find_revision+0x88/0x200 [ 43.812219] nfnl_compat_get+0x1f7/0x870 [ 43.816788] nfnetlink_rcv_msg+0x9bb/0xc00 [ 43.821519] netlink_rcv_skb+0x125/0x390 [ 43.826088] nfnetlink_rcv+0x1ab/0x1da0 [ 43.830557] netlink_unicast+0x437/0x610 [ 43.835122] netlink_sendmsg+0x62e/0xb80 [ 43.839679] sock_sendmsg+0xb5/0x100 [ 43.843887] ___sys_sendmsg+0x6c8/0x800 [ 43.848353] __sys_sendmsg+0xa3/0x120 [ 43.852646] SyS_sendmsg+0x27/0x40 [ 43.856682] do_syscall_64+0x1d5/0x640 [ 43.861064] entry_SYSCALL_64_after_hwframe+0x46/0xbb [ 43.866748] [ 43.866748] -> #0 (&table[i].mutex){+.+.}: [ 43.872441] lock_acquire+0x170/0x3f0 [ 43.876742] __mutex_lock+0xc4/0x1310 [ 43.881054] nf_tables_netdev_event+0x10d/0x4d0 [ 43.886220] notifier_call_chain+0x108/0x1a0 [ 43.891123] rollback_registered_many+0x70b/0xb30 [ 43.896472] unregister_netdevice_many.part.0+0x18/0x2e0 [ 43.902420] unregister_netdevice_many+0x36/0x50 [ 43.907683] ip6gre_exit_net+0x41e/0x570 [ 43.912242] ops_exit_list+0xa5/0x150 [ 43.916545] cleanup_net+0x3b3/0x840 [ 43.920769] process_one_work+0x793/0x14a0 [ 43.925510] worker_thread+0x5cc/0xff0 [ 43.929892] kthread+0x30d/0x420 [ 43.934126] ret_from_fork+0x24/0x30 [ 43.938330] [ 43.938330] other info that might help us debug this: [ 43.938330] [ 43.946440] Chain exists of: [ 43.946440] &table[i].mutex --> &xt[i].mutex --> rtnl_mutex [ 43.946440] [ 43.956661] Possible unsafe locking scenario: [ 43.956661] [ 43.962691] CPU0 CPU1 [ 43.967774] ---- ---- [ 43.972438] lock(rtnl_mutex); [ 43.975694] lock(&xt[i].mutex); [ 43.981670] lock(rtnl_mutex); [ 43.987491] lock(&table[i].mutex); [ 43.991182] [ 43.991182] *** DEADLOCK *** [ 43.991182] [ 43.997227] 4 locks held by kworker/u4:3/110: [ 44.001707] #0: ("%s""netns"){+.+.}, at: [] process_one_work+0x6b0/0x14a0 [ 44.010363] #1: (net_cleanup_work){+.+.}, at: [] process_one_work+0x6e6/0x14a0 [ 44.019456] #2: (net_mutex){+.+.}, at: [] cleanup_net+0x110/0x840 [ 44.027407] #3: (rtnl_mutex){+.+.}, at: [] ip6gre_exit_net+0x70/0x570 [ 44.035706] [ 44.035706] stack backtrace: [ 44.040189] CPU: 0 PID: 110 Comm: kworker/u4:3 Not tainted 4.14.191-syzkaller #0 [ 44.047698] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.057048] Workqueue: netns cleanup_net [ 44.061080] Call Trace: [ 44.063906] dump_stack+0x1b2/0x283 [ 44.067523] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 44.073307] __lock_acquire+0x2e0e/0x3f20 [ 44.077475] ? unwind_next_frame+0x404/0x17d0 [ 44.081943] ? trace_hardirqs_on+0x10/0x10 [ 44.086152] ? check_usage_forwards+0x2d0/0x2d0 [ 44.090795] ? ret_from_fork+0x24/0x30 [ 44.094671] lock_acquire+0x170/0x3f0 [ 44.098445] ? nf_tables_netdev_event+0x10d/0x4d0 [ 44.103276] ? nf_tables_netdev_event+0x10d/0x4d0 [ 44.108092] __mutex_lock+0xc4/0x1310 [ 44.111867] ? nf_tables_netdev_event+0x10d/0x4d0 [ 44.116685] ? nf_tables_netdev_event+0x10d/0x4d0 [ 44.121503] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 44.126929] ? trace_hardirqs_on+0x10/0x10 [ 44.131150] ? trace_hardirqs_on_caller+0x3a8/0x580 [ 44.136141] ? lock_downgrade+0x740/0x740 [ 44.140263] nf_tables_netdev_event+0x10d/0x4d0 [ 44.144907] ? mirred_device_event+0x12f/0x170 [ 44.149462] ? nf_tables_netdev_init_net+0x140/0x140 [ 44.154561] ? mirred_device_event+0x12f/0x170 [ 44.159123] ? __local_bh_enable_ip+0xc1/0x170 [ 44.163712] notifier_call_chain+0x108/0x1a0 [ 44.168099] rollback_registered_many+0x70b/0xb30 [ 44.172952] ? __ww_mutex_wakeup_for_backoff+0x210/0x210 [ 44.178377] ? dev_set_mac_address+0x2d0/0x2d0 [ 44.182967] ? lock_acquire+0x170/0x3f0 [ 44.186915] unregister_netdevice_many.part.0+0x18/0x2e0 [ 44.192454] unregister_netdevice_many+0x36/0x50 [ 44.197218] ip6gre_exit_net+0x41e/0x570 [ 44.201253] ? lock_downgrade+0x740/0x740 [ 44.205375] ? ip6gre_dellink+0x260/0x260 [ 44.216369] ? ip6gre_dellink+0x260/0x260 [ 44.220489] ops_exit_list+0xa5/0x150 [ 44.224262] cleanup_net+0x3b3/0x840 [ 44.227950] ? net_drop_ns+0x70/0x70 [ 44.231637] ? lock_acquire+0x170/0x3f0 [ 44.235597] ? rcu_lockdep_current_cpu_online+0xed/0x140 [ 44.241022] process_one_work+0x793/0x14a0 [ 44.245243] ? work_busy+0x320/0x320 [ 44.248929] ? worker_thread+0x158/0xff0 [ 44.252979] ? _raw_spin_unlock_irq+0x24/0x80 [ 44.257552] worker_thread+0x5cc/0xff0 [ 44.261439] ? rescuer_thread+0xc80/0xc80 [ 44.265559] kthread+0x30d/0x420 [ 44.268898] ? kthread_create_on_node+0xd0/0xd0 [ 44.273539] ret_from_fork+0x24/0x30 [ 45.545675] IPVS: ftp: loaded support on port[0] = 21 executing program [ 46.447084] ip6_tables: ip6tables: counters copy to user failed while replacing table [ 47.835002] IPVS: ftp: loaded support on port[0] = 21 executing program [ 48.756411] ip6_tables: ip6tables: counters copy to user failed while replacing table [ 50.104425] IPVS: ftp: loaded support on port[0] = 21 executing program [ 50.985972] ip6_tables: ip6tables: counters copy to user failed while replacing table [ 52.293985] IPVS: ftp: loaded support on port[0] = 21 executing program [ 53.114982] ip6_tables: ip6tables: counters copy to user failed while replacing table