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 'ci-upstream-mmots-kasan-gce-5,10.128.0.43' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.266540] refcount_t: underflow; use-after-free. [ 41.271623] ------------[ cut here ]------------ [ 41.276487] WARNING: CPU: 1 PID: 2992 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 41.285640] Kernel panic - not syncing: panic_on_warn set ... [ 41.285640] [ 41.292976] CPU: 1 PID: 2992 Comm: syzkaller813086 Not tainted 4.13.0-mm1+ #7 [ 41.300220] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.309543] Call Trace: [ 41.312104] dump_stack+0x194/0x257 [ 41.315705] ? arch_local_irq_restore+0x53/0x53 [ 41.320355] panic+0x1e4/0x417 [ 41.323519] ? __warn+0x1d9/0x1d9 [ 41.326940] ? show_regs_print_info+0x65/0x65 [ 41.331420] ? refcount_sub_and_test+0x167/0x1b0 [ 41.336148] __warn+0x1c4/0x1d9 [ 41.339399] ? refcount_sub_and_test+0x167/0x1b0 [ 41.344129] report_bug+0x211/0x2d0 [ 41.347736] fixup_bug+0x40/0x90 [ 41.351074] do_trap+0x260/0x390 [ 41.354415] do_error_trap+0x120/0x390 [ 41.358279] ? do_trap+0x390/0x390 [ 41.361793] ? refcount_sub_and_test+0x167/0x1b0 [ 41.366537] ? vprintk_emit+0x3ea/0x590 [ 41.370492] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.375310] do_invalid_op+0x1b/0x20 [ 41.378995] invalid_op+0x18/0x20 [ 41.382419] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 41.387752] RSP: 0018:ffff8801ce74e300 EFLAGS: 00010282 [ 41.393089] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 41.400329] RDX: 0000000000000026 RSI: 1ffff10039ce9c20 RDI: ffffed0039ce9c54 [ 41.407580] RBP: ffff8801ce74e390 R08: ffff8801ce74d9f0 R09: 0000000000000000 [ 41.414821] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039ce9c61 [ 41.422065] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce2f1364 [ 41.429331] ? refcount_inc+0x50/0x50 [ 41.433114] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 41.437839] ? sctp_association_free+0x2d0/0x930 [ 41.442568] ? sctp_do_sm+0x28e7/0x6dd0 [ 41.446510] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.451234] ? sctp_close+0x3c6/0x980 [ 41.455009] ? inet_release+0xed/0x1c0 [ 41.458875] sctp_wfree+0x183/0x620 [ 41.462473] ? __sctp_write_space+0x910/0x910 [ 41.466953] skb_release_head_state+0x124/0x200 [ 41.471620] skb_release_all+0x15/0x60 [ 41.475489] consume_skb+0x153/0x490 [ 41.479172] ? sctp_chunk_put+0x99/0x420 [ 41.483205] ? alloc_skb_with_frags+0x710/0x710 [ 41.487844] ? sctp_chunk_hold+0x20/0x20 [ 41.491880] ? refcount_sub_and_test+0x115/0x1b0 [ 41.496605] ? refcount_inc+0x50/0x50 [ 41.500375] ? mark_held_locks+0xb2/0x100 [ 41.504495] ? sctp_datamsg_put+0x456/0x560 [ 41.508792] sctp_chunk_put+0x29c/0x420 [ 41.512741] ? sctp_chunk_hold+0x20/0x20 [ 41.516777] ? sctp_transport_dst_confirm+0x50/0x50 [ 41.521781] sctp_chunk_free+0x53/0x60 [ 41.525640] __sctp_outq_teardown+0xc7d/0x15a0 [ 41.530207] ? inet6_release+0x50/0x70 [ 41.534073] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 41.538975] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.543967] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.548958] ? unwind_dump+0x4c0/0x4c0 [ 41.552820] ? unwind_dump+0x4c0/0x4c0 [ 41.556683] ? copy_trace+0x1d0/0x1d0 [ 41.560460] ? check_noncircular+0x20/0x20 [ 41.564669] ? check_noncircular+0x20/0x20 [ 41.568873] ? unwind_get_return_address+0x61/0xa0 [ 41.573779] ? __save_stack_trace+0x61/0xd0 [ 41.578081] ? check_noncircular+0x20/0x20 [ 41.582291] ? print_usage_bug+0x480/0x480 [ 41.586504] ? find_held_lock+0x39/0x1d0 [ 41.590545] ? lock_downgrade+0x990/0x990 [ 41.594669] ? sk_dst_check+0x560/0x560 [ 41.598615] ? rcu_read_lock_sched_held+0x108/0x120 [ 41.603605] ? lock_release+0xd70/0xd70 [ 41.607559] sctp_outq_free+0x15/0x20 [ 41.611332] sctp_association_free+0x2d0/0x930 [ 41.615891] ? sctp_asconf_queue_teardown+0x700/0x700 [ 41.621054] ? sock_def_wakeup+0x222/0x350 [ 41.625263] ? sk_dst_check+0x560/0x560 [ 41.629224] ? sctp_association_put+0x74/0x2f0 [ 41.633777] ? sctp_association_hold+0x20/0x20 [ 41.638336] ? __unwind_start+0x169/0x330 [ 41.642465] ? sctp_sm_lookup_event+0x95/0x3c0 [ 41.647024] sctp_do_sm+0x28e7/0x6dd0 [ 41.650810] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 41.656849] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 41.662012] ? print_usage_bug+0x480/0x480 [ 41.666219] ? print_usage_bug+0x480/0x480 [ 41.670426] ? find_held_lock+0x39/0x1d0 [ 41.674467] ? lock_downgrade+0x990/0x990 [ 41.678593] ? skb_dequeue+0x22/0x180 [ 41.682372] ? do_raw_spin_trylock+0x190/0x190 [ 41.686946] ? mark_held_locks+0xb2/0x100 [ 41.691072] ? trace_hardirqs_on+0xd/0x10 [ 41.695199] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.699755] sctp_close+0x3c6/0x980 [ 41.703362] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 41.708610] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 41.713596] ? trace_hardirqs_on+0xd/0x10 [ 41.717726] ? rcu_eqs_enter_common.constprop.73+0x270/0x270 [ 41.723500] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 41.727970] ? ipv6_sock_mc_close+0x148/0x1a0 [ 41.732434] ? ipv6_sock_ac_drop+0x580/0x580 [ 41.736815] ? ip_mc_drop_socket+0x1ce/0x230 [ 41.741202] ? __fsnotify_parent+0xb4/0x3a0 [ 41.745503] inet_release+0xed/0x1c0 [ 41.749195] inet6_release+0x50/0x70 [ 41.752885] sock_release+0x8d/0x1e0 [ 41.756573] ? sock_release+0x1e0/0x1e0 [ 41.760528] sock_close+0x16/0x20 [ 41.763960] __fput+0x333/0x7f0 [ 41.767219] ? fput+0x140/0x140 [ 41.770486] ? check_same_owner+0x320/0x320 [ 41.774787] ____fput+0x15/0x20 [ 41.778043] task_work_run+0x199/0x270 [ 41.781907] ? task_work_cancel+0x210/0x210 [ 41.786217] ? free_nsproxy+0x185/0x1f0 [ 41.790166] ? switch_task_namespaces+0xa2/0xc0 [ 41.794815] do_exit+0xa52/0x1b40 [ 41.798248] ? print_usage_bug+0x480/0x480 [ 41.802466] ? mm_update_next_owner+0x930/0x930 [ 41.807115] ? find_held_lock+0x39/0x1d0 [ 41.811156] ? check_noncircular+0x20/0x20 [ 41.815367] ? check_noncircular+0x20/0x20 [ 41.819575] ? lock_downgrade+0x990/0x990 [ 41.823706] ? reacquire_held_locks+0x205/0x3d0 [ 41.828350] ? check_noncircular+0x20/0x20 [ 41.832556] ? find_held_lock+0x39/0x1d0 [ 41.836601] ? lock_downgrade+0x990/0x990 [ 41.840722] ? lock_downgrade+0x990/0x990 [ 41.844845] ? find_held_lock+0x39/0x1d0 [ 41.848888] ? lock_downgrade+0x990/0x990 [ 41.853011] ? recalc_sigpending_tsk+0x117/0x150 [ 41.857745] ? recalc_sigpending+0x103/0x160 [ 41.862126] ? recalc_sigpending_tsk+0x150/0x150 [ 41.866851] ? get_signal+0x397/0x17e0 [ 41.870729] do_group_exit+0x149/0x400 [ 41.874592] ? __lock_is_held+0xbc/0x140 [ 41.878633] ? SyS_exit+0x30/0x30 [ 41.882070] ? _raw_spin_unlock_irq+0x27/0x70 [ 41.886550] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 41.891543] get_signal+0x7e8/0x17e0 [ 41.895259] ? ptrace_notify+0x130/0x130 [ 41.899303] ? __local_bh_enable_ip+0x9d/0x160 [ 41.903866] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 41.908867] ? release_sock+0x1d4/0x2a0 [ 41.912818] ? trace_hardirqs_on+0xd/0x10 [ 41.916937] ? __local_bh_enable_ip+0x9d/0x160 [ 41.921493] ? _raw_spin_unlock_bh+0x30/0x40 [ 41.925874] ? release_sock+0x1d4/0x2a0 [ 41.929825] ? trace_hardirqs_on+0xd/0x10 [ 41.933952] do_signal+0x94/0x1ee0 [ 41.937467] ? inet_sendmsg+0x11f/0x5e0 [ 41.941409] ? inet_sendmsg+0x126/0x5e0 [ 41.945357] ? __might_sleep+0x95/0x190 [ 41.949305] ? setup_sigcontext+0x7d0/0x7d0 [ 41.953613] ? selinux_socket_sendmsg+0x36/0x40 [ 41.958268] ? security_socket_sendmsg+0x89/0xb0 [ 41.963006] ? inet_recvmsg+0x5f0/0x5f0 [ 41.966960] ? sock_sendmsg+0x4f/0x110 [ 41.970822] ? fput+0xd2/0x140 [ 41.973991] ? SYSC_sendto+0x413/0x5a0 [ 41.977860] ? SYSC_connect+0x480/0x480 [ 41.981803] ? __handle_mm_fault+0x39c0/0x39c0 [ 41.986366] ? exit_to_usermode_loop+0x98/0x300 [ 41.991014] exit_to_usermode_loop+0x224/0x300 [ 41.995570] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 42.001080] ? __do_page_fault+0xb60/0xb60 [ 42.005288] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.010283] syscall_return_slowpath+0x42f/0x500 [ 42.015011] ? finish_task_switch+0x1aa/0x740 [ 42.019489] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 42.024830] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 42.029733] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.034729] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.039463] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 42.044191] RIP: 0033:0x445da9 [ 42.047353] RSP: 002b:00007fae952aedb8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 42.055034] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000445da9 [ 42.062274] RDX: 0000000000000001 RSI: 0000000020018fff RDI: 0000000000000003 [ 42.069513] RBP: 0000000000000000 R08: 00000000206e4000 R09: 000000000000001c [ 42.076753] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 [ 42.084413] R13: 00000000007efe8f R14: 00007fae952af9c0 R15: 0000000000000000 [ 42.091823] Dumping ftrace buffer: [ 42.095494] (ftrace buffer empty) [ 42.099178] Kernel Offset: disabled [ 42.102782] Rebooting in 86400 seconds..