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 '10.128.10.21' (ECDSA) to the list of known hosts. syzkaller login: [ 30.235049] IPVS: ftp: loaded support on port[0] = 21 [ 30.242357] IPVS: ftp: loaded support on port[0] = 21 [ 30.247530] IPVS: ftp: loaded support on port[0] = 21 [ 30.249065] IPVS: ftp: loaded support on port[0] = 21 [ 30.254123] IPVS: ftp: loaded support on port[0] = 21 [ 30.258738] IPVS: ftp: loaded support on port[0] = 21 [ 30.264194] IPVS: ftp: loaded support on port[0] = 21 [ 30.276103] IPVS: ftp: loaded support on port[0] = 21 [ 30.403494] IPVS: stopping backup sync thread 4458 ... [ 30.407525] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.432526] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.438137] IPVS: stopping backup sync thread 4465 ... [ 30.448590] IPVS: stopping backup sync thread 4468 ... [ 30.469272] IPVS: stopping backup sync thread 4473 ... [ 30.477295] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.488598] IPVS: stopping backup sync thread 4480 ... [ 30.494450] IPVS: stopping backup sync thread 4483 ... [ 30.503588] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.505922] IPVS: stopping backup sync thread 4487 ... [ 30.518132] IPVS: stopping backup sync thread 4491 ... [ 30.520084] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.524523] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.532609] IPVS: stopping backup sync thread 4495 ... [ 30.544960] IPVS: stopping backup sync thread 4497 ... [ 30.546823] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.553665] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.569515] IPVS: sync thread started: state = BACKUP, mcast_ifn = sit0, syncid = 0, id = 0 [ 30.570804] [ 30.579626] ============================================ [ 30.585062] WARNING: possible recursive locking detected [ 30.590493] 4.16.0+ #19 Not tainted [ 30.594093] -------------------------------------------- [ 30.599518] syzkaller972902/4494 is trying to acquire lock: [ 30.604593] IPVS: stopping backup sync thread 4501 ... [ 30.605204] 000000003fd9b4cb (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 [ 30.605241] [ 30.605241] but task is already holding lock: [ 30.605248] 000000003fd9b4cb [ 30.613646] IPVS: stopping backup sync thread 4502 ... [ 30.617321] (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 [ 30.617349] [ 30.617349] other info that might help us debug this: [ 30.617353] Possible unsafe locking scenario: [ 30.617353] [ 30.617355] CPU0 [ 30.617357] ---- [ 30.617359] lock(rtnl_mutex); [ 30.617365] lock(rtnl_mutex); [ 30.661287] [ 30.661287] *** DEADLOCK *** [ 30.661287] [ 30.667323] May be due to missing lock nesting notation [ 30.667323] [ 30.674231] 2 locks held by syzkaller972902/4494: [ 30.679051] #0: 000000003fd9b4cb (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 [ 30.686339] #1: 0000000030997897 (ipvs->sync_mutex){+.+.}, at: do_ip_vs_set_ctl+0x562/0x1d30 [ 30.694994] [ 30.694994] stack backtrace: [ 30.699479] CPU: 1 PID: 4494 Comm: syzkaller972902 Not tainted 4.16.0+ #19 [ 30.706466] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 30.715794] Call Trace: [ 30.718376] dump_stack+0x1b9/0x294 [ 30.721993] ? dump_stack_print_info.cold.2+0x52/0x52 [ 30.727168] ? print_lock+0xd1/0xd6 [ 30.730774] ? vprintk_func+0x81/0xe7 [ 30.734552] __lock_acquire.cold.62+0x18c/0x55b [ 30.739204] ? debug_check_no_locks_freed+0x310/0x310 [ 30.744375] ? __enqueue_entity+0x10d/0x1f0 [ 30.748676] ? __lock_is_held+0xb5/0x140 [ 30.752714] ? __lock_acquire+0x7f5/0x5130 [ 30.756927] ? update_curr+0x332/0xbf0 [ 30.760795] ? debug_check_no_locks_freed+0x310/0x310 [ 30.765969] ? select_idle_sibling+0xd80/0xd80 [ 30.770537] ? lock_downgrade+0x8e0/0x8e0 [ 30.774665] ? graph_lock+0x170/0x170 [ 30.778447] ? kasan_check_read+0x11/0x20 [ 30.782574] ? graph_lock+0x170/0x170 [ 30.786353] ? graph_lock+0x170/0x170 [ 30.790141] lock_acquire+0x1dc/0x520 [ 30.793922] ? rtnl_lock+0x17/0x20 [ 30.797440] ? lock_release+0xa10/0xa10 [ 30.801396] ? check_same_owner+0x320/0x320 [ 30.805694] ? graph_lock+0x170/0x170 [ 30.809477] ? rcu_note_context_switch+0x710/0x710 [ 30.814395] ? __might_sleep+0x95/0x190 [ 30.818351] ? rtnl_lock+0x17/0x20 [ 30.821870] __mutex_lock+0x16d/0x17f0 [ 30.825738] ? rtnl_lock+0x17/0x20 [ 30.829254] ? rtnl_lock+0x17/0x20 [ 30.832775] ? mutex_trylock+0x2a0/0x2a0 [ 30.836814] ? mark_held_locks+0xc9/0x160 [ 30.840939] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 30.845502] ? _raw_spin_unlock_irq+0x27/0x70 [ 30.849977] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 30.854971] ? trace_hardirqs_on+0xd/0x10 [ 30.859105] ? _raw_spin_unlock_irq+0x27/0x70 [ 30.863586] ? wait_for_completion_killable+0x56c/0x960 [ 30.868940] ? wait_for_completion_interruptible_timeout+0x960/0x960 [ 30.875422] ? lock_downgrade+0x8e0/0x8e0 [ 30.879557] ? kasan_check_read+0x11/0x20 [ 30.883682] ? do_raw_spin_unlock+0x9e/0x2e0 [ 30.888069] ? do_raw_spin_trylock+0x1b0/0x1b0 [ 30.892641] ? wake_up_q+0x100/0x100 [ 30.896339] ? kasan_check_write+0x14/0x20 [ 30.900558] ? do_raw_spin_lock+0xc1/0x200 [ 30.904786] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 30.910309] ? __kthread_create_on_node+0x34f/0x4c0 [ 30.915306] ? __kthread_parkme+0x280/0x280 [ 30.919607] ? kasan_check_read+0x11/0x20 [ 30.923733] ? do_raw_spin_unlock+0x9e/0x2e0 [ 30.928120] ? __lock_is_held+0xb5/0x140 [ 30.932163] mutex_lock_nested+0x16/0x20 [ 30.936204] ? mutex_lock_nested+0x16/0x20 [ 30.940418] rtnl_lock+0x17/0x20 [ 30.943766] ip_mc_drop_socket+0x8f/0x270 [ 30.947892] inet_release+0x4e/0x1f0 [ 30.951595] sock_release+0x96/0x1b0 [ 30.955288] start_sync_thread+0xdc3/0x2d40 [ 30.959589] ? ip_vs_process_message+0xa0a/0xa0a [ 30.964324] ? ip_vs_sync_conn+0x33a0/0x33a0 [ 30.968714] ? graph_lock+0x170/0x170 [ 30.972491] ? lock_downgrade+0x8e0/0x8e0 [ 30.976617] ? kasan_check_read+0x11/0x20 [ 30.980743] ? do_raw_spin_unlock+0x9e/0x2e0 [ 30.985135] ? find_held_lock+0x36/0x1c0 [ 30.989197] ? lock_downgrade+0x8e0/0x8e0 [ 30.993324] ? __release_sock+0x3a0/0x3a0 [ 30.997453] ? lock_release+0xa10/0xa10 [ 31.001434] ? check_same_owner+0x320/0x320 [ 31.005754] ? module_unload_free+0x5b0/0x5b0 [ 31.010241] do_ip_vs_set_ctl+0x59c/0x1d30 [ 31.014478] ? ip_vs_genl_set_cmd+0xe80/0xe80 [ 31.018955] ? lock_downgrade+0x8e0/0x8e0 [ 31.023085] ? kasan_check_read+0x11/0x20 [ 31.027212] ? rcu_is_watching+0x85/0x140 [ 31.031339] ? rcu_bh_force_quiescent_state+0x20/0x20 [ 31.036519] ? kasan_check_write+0x14/0x20 [ 31.040744] ? __mutex_unlock_slowpath+0x180/0x8a0 [ 31.045653] ? wait_for_completion+0x870/0x870 [ 31.050215] ? graph_lock+0x170/0x170 [ 31.054004] ? module_unload_free+0x5b0/0x5b0 [ 31.058481] ? find_held_lock+0x36/0x1c0 [ 31.062524] nf_setsockopt+0x7d/0xd0 [ 31.066219] ? ip_vs_genl_set_cmd+0xe80/0xe80 [ 31.070693] ? nf_setsockopt+0x7d/0xd0 [ 31.074560] ip_setsockopt+0xd8/0xf0 [ 31.078263] udp_setsockopt+0x62/0xa0 [ 31.082049] sock_common_setsockopt+0x9a/0xe0 [ 31.086525] __sys_setsockopt+0x1bd/0x390 [ 31.090660] ? kernel_accept+0x310/0x310 [ 31.094703] ? mm_fault_error+0x380/0x380 [ 31.098831] ? syscall_slow_exit_work+0x4f0/0x4f0 [ 31.103663] SyS_setsockopt+0x34/0x50 [ 31.107445] ? SyS_recv+0x40/0x40 [ 31.110878] do_syscall_64+0x29e/0x9d0 [ 31.114757] ? vmalloc_sync_all+0x30/0x30 [ 31.118891] ? syscall_slow_exit_work+0x4f0/0x4f0 [ 31.123721] ? syscall_return_slowpath+0x5c0/0x5c0 [ 31.128630] ? syscall_return_slowpath+0x30f/0x5c0 [ 31.133569] ? __sanitizer_cov_trace_const_cmp4+0x16/0x20 [ 31.139089] ? retint_user+0x18/0x18 [ 31.142791] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.147619] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 31.152788] RIP: 0033:0x44a729 [ 31.155964] RSP: 002b:00007f0c4fa42da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 [ 31.163665] RAX: ffffffffffffffda RBX: 00000000006e29e4 RCX: 000000000044a729 [ 31.170920] RDX: 000000000000048b RSI: 0000000000000000 RDI: 0000000000000004 [ 31.178166] RBP: 0000000000000000 R08: 0000000000000018 R09: 0000000000000000 [ 31.185423] R10: 0000000020000040 R11: 0000000000000246 R12: 00000000006e29e0 [ 31.192685] R13: 6e69622f7665642f R14: 1100000000000000 R15: 00000000006e2b60