INIT: Entering runlevel: 2 [info] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[ ok 8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[ ok 8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added '10.128.0.20' (ECDSA) to the list of known hosts. 2018/04/13 10:21:24 parsed 1 programs 2018/04/13 10:21:24 executed programs: 0 syzkaller login: [ 30.301954] IPVS: ftp: loaded support on port[0] = 21 [ 30.303842] IPVS: ftp: loaded support on port[0] = 21 [ 30.318998] IPVS: ftp: loaded support on port[0] = 21 [ 30.343654] IPVS: ftp: loaded support on port[0] = 21 [ 30.343814] IPVS: ftp: loaded support on port[0] = 21 [ 30.363636] IPVS: ftp: loaded support on port[0] = 21 [ 30.363706] IPVS: ftp: loaded support on port[0] = 21 [ 30.386066] IPVS: ftp: loaded support on port[0] = 21 [ 30.500262] IPVS: stopping backup sync thread 4506 ... [ 30.511187] IPVS: sync thread started: state = BACKUP, mcast_ifn = lo, syncid = 0, id = 0 [ 30.522609] IPVS: stopping backup sync thread 4512 ... [ 30.560736] [ 30.562386] ============================================ [ 30.567820] WARNING: possible recursive locking detected [ 30.573260] 4.16.0+ #2 Not tainted [ 30.576785] -------------------------------------------- [ 30.582221] syz-executor6/4513 is trying to acquire lock: [ 30.582765] IPVS: stopping backup sync thread 4508 ... [ 30.587748] 00000000692d5859 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 [ 30.587777] [ 30.587777] but task is already holding lock: [ 30.605789] 00000000692d5859 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 [ 30.612615] [ 30.612615] other info that might help us debug this: [ 30.619253] Possible unsafe locking scenario: [ 30.619253] [ 30.625282] CPU0 [ 30.627836] ---- [ 30.630392] lock(rtnl_mutex); [ 30.633647] lock(rtnl_mutex); [ 30.636898] [ 30.636898] *** DEADLOCK *** [ 30.636898] [ 30.642930] May be due to missing lock nesting notation [ 30.642930] [ 30.649833] 2 locks held by syz-executor6/4513: [ 30.654479] #0: 00000000692d5859 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 [ 30.661742] #1: 000000004d97917a (ipvs->sync_mutex){+.+.}, at: do_ip_vs_set_ctl+0x562/0x1d30 [ 30.670409] [ 30.670409] stack backtrace: [ 30.674884] CPU: 0 PID: 4513 Comm: syz-executor6 Not tainted 4.16.0+ #2 [ 30.681611] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.690939] Call Trace: [ 30.693510] dump_stack+0x1b9/0x294 [ 30.697115] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.702282] ? print_lock+0xd1/0xd6 [ 30.705884] ? vprintk_func+0x81/0xe7 [ 30.709670] __lock_acquire.cold.62+0x18c/0x55b [ 30.714319] ? debug_check_no_locks_freed+0x310/0x310 [ 30.719491] ? graph_lock+0x170/0x170 [ 30.723271] ? pick_next_task_fair+0x973/0x1660 [ 30.727915] ? __lock_is_held+0xb5/0x140 [ 30.731957] ? __lock_acquire+0x7f5/0x5130 [ 30.736166] ? print_usage_bug+0xc0/0xc0 [ 30.740205] ? finish_task_switch+0x182/0x810 [ 30.744677] ? mark_held_locks+0xc9/0x160 [ 30.748802] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 30.753368] ? graph_lock+0x170/0x170 [ 30.757150] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.762143] ? trace_hardirqs_on+0xd/0x10 [ 30.766269] ? _raw_spin_unlock_irq+0x27/0x70 [ 30.770742] ? finish_task_switch+0x1ca/0x810 [ 30.775214] ? finish_task_switch+0x182/0x810 [ 30.779686] lock_acquire+0x1dc/0x520 [ 30.783467] ? rtnl_lock+0x17/0x20 [ 30.786984] ? lock_release+0xa10/0xa10 [ 30.790937] ? check_same_owner+0x320/0x320 [ 30.795244] ? __schedule+0x809/0x1e30 [ 30.799109] ? rcu_note_context_switch+0x710/0x710 [ 30.804020] ? __might_sleep+0x95/0x190 [ 30.807978] ? rtnl_lock+0x17/0x20 [ 30.811506] __mutex_lock+0x16d/0x17f0 [ 30.815373] ? rtnl_lock+0x17/0x20 [ 30.818908] ? rtnl_lock+0x17/0x20 [ 30.822444] ? mutex_trylock+0x2a0/0x2a0 [ 30.826483] ? mark_held_locks+0xc9/0x160 [ 30.830618] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 30.835185] ? _raw_spin_unlock_irq+0x27/0x70 [ 30.839655] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.844650] ? trace_hardirqs_on+0xd/0x10 [ 30.848775] ? _raw_spin_unlock_irq+0x27/0x70 [ 30.853245] ? wait_for_completion_killable+0x56c/0x960 [ 30.858587] ? wait_for_completion_interruptible_timeout+0x960/0x960 [ 30.865056] ? lock_downgrade+0x8e0/0x8e0 [ 30.869181] ? kasan_check_read+0x11/0x20 [ 30.873306] ? do_raw_spin_unlock+0x9e/0x2e0 [ 30.877691] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 30.882249] ? wake_up_q+0x100/0x100 [ 30.885938] ? kasan_check_write+0x14/0x20 [ 30.890154] ? do_raw_spin_lock+0xc1/0x200 [ 30.894366] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.899876] ? __kthread_create_on_node+0x34f/0x4c0 [ 30.904869] ? __kthread_parkme+0x280/0x280 [ 30.909165] ? kasan_check_read+0x11/0x20 [ 30.913289] ? do_raw_spin_unlock+0x9e/0x2e0 [ 30.917673] ? __lock_is_held+0xb5/0x140 [ 30.921712] mutex_lock_nested+0x16/0x20 [ 30.925755] ? mutex_lock_nested+0x16/0x20 [ 30.929966] rtnl_lock+0x17/0x20 [ 30.933312] ip_mc_drop_socket+0x8f/0x270 [ 30.937440] inet_release+0x4e/0x1f0 [ 30.941132] sock_release+0x96/0x1b0 [ 30.944823] start_sync_thread+0xdc3/0x2d40 [ 30.949122] ? ip_vs_process_message+0xa0a/0xa0a [ 30.953868] ? ip_vs_sync_conn+0x33a0/0x33a0 [ 30.958255] ? graph_lock+0x170/0x170 [ 30.962034] ? lock_downgrade+0x8e0/0x8e0 [ 30.966159] ? kasan_check_read+0x11/0x20 [ 30.970282] ? do_raw_spin_unlock+0x9e/0x2e0 [ 30.974665] ? find_held_lock+0x36/0x1c0 [ 30.978715] ? lock_downgrade+0x8e0/0x8e0 [ 30.982844] ? __release_sock+0x3a0/0x3a0 [ 30.986969] ? lock_release+0xa10/0xa10 [ 30.990919] ? check_same_owner+0x320/0x320 [ 30.995220] ? module_unload_free+0x5b0/0x5b0 [ 30.999694] do_ip_vs_set_ctl+0x59c/0x1d30 [ 31.003905] ? ip_vs_genl_set_cmd+0xe80/0xe80 [ 31.008378] ? lock_downgrade+0x8e0/0x8e0 [ 31.012504] ? kasan_check_read+0x11/0x20 [ 31.016628] ? rcu_is_watching+0x85/0x140 [ 31.020752] ? rcu_bh_force_quiescent_state+0x20/0x20 [ 31.025918] ? kasan_check_write+0x14/0x20 [ 31.030132] ? __mutex_unlock_slowpath+0x180/0x8a0 [ 31.035040] ? wait_for_completion+0x870/0x870 [ 31.039600] ? module_unload_free+0x5b0/0x5b0 [ 31.044074] nf_setsockopt+0x7d/0xd0 [ 31.047762] ? ip_vs_genl_set_cmd+0xe80/0xe80 [ 31.052230] ? nf_setsockopt+0x7d/0xd0 [ 31.056095] ip_setsockopt+0xd8/0xf0 [ 31.059786] udp_setsockopt+0x62/0xa0 [ 31.063563] sock_common_setsockopt+0x9a/0xe0 [ 31.068043] __sys_setsockopt+0x1bd/0x390 [ 31.072167] ? kernel_accept+0x310/0x310 [ 31.076203] ? lock_downgrade+0x8e0/0x8e0 [ 31.080328] ? kasan_check_read+0x11/0x20 [ 31.084453] ? do_raw_spin_unlock+0x9e/0x2e0 [ 31.088838] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 31.093396] SyS_setsockopt+0x34/0x50 [ 31.097171] ? SyS_recv+0x40/0x40 [ 31.100603] do_syscall_64+0x29e/0x9d0 [ 31.104465] ? _raw_spin_unlock_irq+0x27/0x70 [ 31.108939] ? finish_task_switch+0x1ca/0x810 [ 31.113413] ? syscall_return_slowpath+0x5c0/0x5c0 [ 31.118319] ? syscall_return_slowpath+0x30f/0x5c0 [ 31.123240] ? entry_SYSCALL_64_after_hwframe+0x52/0xb7 [ 31.128583] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.133404] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 31.138569] RIP: 0033:0x455319 [ 31.141735] RSP: 002b:00007f5022c0fc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 [ 31.149417] RAX: ffffffffffffffda RBX: 00007f5022c106d4 RCX: 0000000000455319 [ 31.156665] RDX: 000000000000048b RSI: 0000000000000000 RDI: 0000000000000004 [ 31.163907] RBP: 000000000072bf58 R08: 0000000000000018 R09: 0000000000000000 [ 31.171160] R10: 0000000020000000 R11: 0000000000000246 R12: 00000000ffffffff [ 31.178410] R13: 0000000000000520 R14: 00000000006faba0 R15: 0000000000000001