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-8,10.128.15.202' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.534608] refcount_t: underflow; use-after-free. [ 41.539707] ------------[ cut here ]------------ [ 41.544616] WARNING: CPU: 1 PID: 2996 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 41.553298] Kernel panic - not syncing: panic_on_warn set ... [ 41.553298] [ 41.560634] CPU: 1 PID: 2996 Comm: syzkaller671903 Not tainted 4.13.0-mm1+ #7 [ 41.567886] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.577212] Call Trace: [ 41.579775] dump_stack+0x194/0x257 [ 41.583377] ? arch_local_irq_restore+0x53/0x53 [ 41.588033] panic+0x1e4/0x417 [ 41.591197] ? __warn+0x1d9/0x1d9 [ 41.594618] ? show_regs_print_info+0x65/0x65 [ 41.599099] ? refcount_sub_and_test+0x167/0x1b0 [ 41.603824] __warn+0x1c4/0x1d9 [ 41.607075] ? refcount_sub_and_test+0x167/0x1b0 [ 41.611804] report_bug+0x211/0x2d0 [ 41.615407] fixup_bug+0x40/0x90 [ 41.618746] do_trap+0x260/0x390 [ 41.622089] do_error_trap+0x120/0x390 [ 41.625948] ? do_trap+0x390/0x390 [ 41.629459] ? refcount_sub_and_test+0x167/0x1b0 [ 41.634183] ? vprintk_emit+0x3ea/0x590 [ 41.638136] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.642958] do_invalid_op+0x1b/0x20 [ 41.646658] invalid_op+0x18/0x20 [ 41.650082] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 41.655412] RSP: 0018:ffff8801ce1fe300 EFLAGS: 00010282 [ 41.660749] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 41.667991] RDX: 0000000000000026 RSI: 1ffff10039c3fc20 RDI: ffffed0039c3fc54 [ 41.675231] RBP: ffff8801ce1fe390 R08: ffff8801ce1fd9f0 R09: 0000000000000000 [ 41.682472] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039c3fc61 [ 41.689714] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce017364 [ 41.696976] ? refcount_inc+0x50/0x50 [ 41.700749] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 41.705479] ? sctp_association_free+0x2d0/0x930 [ 41.710205] ? sctp_do_sm+0x28e7/0x6dd0 [ 41.714149] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.718872] ? sctp_close+0x3c6/0x980 [ 41.722644] ? inet_release+0xed/0x1c0 [ 41.726506] sctp_wfree+0x183/0x620 [ 41.730106] ? __sctp_write_space+0x910/0x910 [ 41.734576] skb_release_head_state+0x124/0x200 [ 41.739219] skb_release_all+0x15/0x60 [ 41.743080] consume_skb+0x153/0x490 [ 41.746763] ? sctp_chunk_put+0x99/0x420 [ 41.750796] ? alloc_skb_with_frags+0x710/0x710 [ 41.755440] ? sctp_chunk_hold+0x20/0x20 [ 41.759475] ? refcount_sub_and_test+0x115/0x1b0 [ 41.764202] ? refcount_inc+0x50/0x50 [ 41.767977] ? mark_held_locks+0xb2/0x100 [ 41.772097] ? sctp_datamsg_put+0x456/0x560 [ 41.776396] sctp_chunk_put+0x29c/0x420 [ 41.780343] ? sctp_chunk_hold+0x20/0x20 [ 41.784379] ? sctp_transport_dst_confirm+0x50/0x50 [ 41.789384] sctp_chunk_free+0x53/0x60 [ 41.793244] __sctp_outq_teardown+0xc7d/0x15a0 [ 41.797801] ? inet6_release+0x50/0x70 [ 41.801666] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 41.806570] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.811564] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.816553] ? unwind_dump+0x4c0/0x4c0 [ 41.820414] ? unwind_dump+0x4c0/0x4c0 [ 41.824277] ? copy_trace+0x1d0/0x1d0 [ 41.828057] ? check_noncircular+0x20/0x20 [ 41.832266] ? check_noncircular+0x20/0x20 [ 41.836471] ? unwind_get_return_address+0x61/0xa0 [ 41.841374] ? __save_stack_trace+0x61/0xd0 [ 41.845669] ? check_noncircular+0x20/0x20 [ 41.849877] ? print_usage_bug+0x480/0x480 [ 41.854090] ? find_held_lock+0x39/0x1d0 [ 41.858135] ? lock_downgrade+0x990/0x990 [ 41.862262] ? sk_dst_check+0x560/0x560 [ 41.866210] ? rcu_read_lock_sched_held+0x108/0x120 [ 41.871204] ? lock_release+0xd70/0xd70 [ 41.875159] sctp_outq_free+0x15/0x20 [ 41.878932] sctp_association_free+0x2d0/0x930 [ 41.883492] ? sctp_asconf_queue_teardown+0x700/0x700 [ 41.888656] ? sock_def_wakeup+0x222/0x350 [ 41.892864] ? sk_dst_check+0x560/0x560 [ 41.896812] ? sctp_association_put+0x74/0x2f0 [ 41.901365] ? sctp_association_hold+0x20/0x20 [ 41.905919] ? __unwind_start+0x169/0x330 [ 41.910045] ? sctp_sm_lookup_event+0x95/0x3c0 [ 41.914599] sctp_do_sm+0x28e7/0x6dd0 [ 41.918382] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 41.924413] ? print_usage_bug+0x480/0x480 [ 41.928622] ? print_usage_bug+0x480/0x480 [ 41.932828] ? find_held_lock+0x39/0x1d0 [ 41.936869] ? lock_downgrade+0x990/0x990 [ 41.940994] ? skb_dequeue+0x22/0x180 [ 41.944773] ? do_raw_spin_trylock+0x190/0x190 [ 41.949332] ? mark_held_locks+0xb2/0x100 [ 41.953461] ? trace_hardirqs_on+0xd/0x10 [ 41.957586] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.962143] sctp_close+0x3c6/0x980 [ 41.965750] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 41.971002] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 41.975993] ? trace_hardirqs_on+0xd/0x10 [ 41.980119] ? rcu_eqs_enter_common.constprop.73+0x270/0x270 [ 41.985887] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 41.990354] ? ipv6_sock_mc_close+0x148/0x1a0 [ 41.994819] ? ipv6_sock_ac_drop+0x580/0x580 [ 41.999200] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.003580] ? __fsnotify_parent+0xb4/0x3a0 [ 42.007875] inet_release+0xed/0x1c0 [ 42.011564] inet6_release+0x50/0x70 [ 42.015250] sock_release+0x8d/0x1e0 [ 42.018933] ? sock_release+0x1e0/0x1e0 [ 42.022876] sock_close+0x16/0x20 [ 42.026300] __fput+0x333/0x7f0 [ 42.029559] ? fput+0x140/0x140 [ 42.032811] ? check_same_owner+0x320/0x320 [ 42.037110] ____fput+0x15/0x20 [ 42.040362] task_work_run+0x199/0x270 [ 42.044223] ? task_work_cancel+0x210/0x210 [ 42.048519] ? free_nsproxy+0x185/0x1f0 [ 42.052470] ? switch_task_namespaces+0xa2/0xc0 [ 42.057119] do_exit+0xa52/0x1b40 [ 42.060544] ? print_usage_bug+0x480/0x480 [ 42.064760] ? mm_update_next_owner+0x930/0x930 [ 42.069401] ? find_held_lock+0x39/0x1d0 [ 42.073438] ? check_noncircular+0x20/0x20 [ 42.077641] ? check_noncircular+0x20/0x20 [ 42.081847] ? lock_downgrade+0x990/0x990 [ 42.085980] ? reacquire_held_locks+0x205/0x3d0 [ 42.090617] ? check_noncircular+0x20/0x20 [ 42.094822] ? find_held_lock+0x39/0x1d0 [ 42.098865] ? lock_downgrade+0x990/0x990 [ 42.102982] ? lock_downgrade+0x990/0x990 [ 42.107114] ? find_held_lock+0x39/0x1d0 [ 42.111154] ? lock_downgrade+0x990/0x990 [ 42.115275] ? recalc_sigpending_tsk+0x117/0x150 [ 42.120005] ? recalc_sigpending+0x103/0x160 [ 42.124386] ? recalc_sigpending_tsk+0x150/0x150 [ 42.129110] ? get_signal+0x397/0x17e0 [ 42.132989] do_group_exit+0x149/0x400 [ 42.136846] ? __lock_is_held+0xbc/0x140 [ 42.140877] ? SyS_exit+0x30/0x30 [ 42.144302] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.148770] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.153762] get_signal+0x7e8/0x17e0 [ 42.157478] ? ptrace_notify+0x130/0x130 [ 42.161510] ? __local_bh_enable_ip+0x9d/0x160 [ 42.166064] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.171052] ? release_sock+0x1d4/0x2a0 [ 42.175013] ? trace_hardirqs_on+0xd/0x10 [ 42.179130] ? __local_bh_enable_ip+0x9d/0x160 [ 42.183683] ? _raw_spin_unlock_bh+0x30/0x40 [ 42.188060] ? release_sock+0x1d4/0x2a0 [ 42.192005] ? __release_sock+0x360/0x360 [ 42.196126] ? trace_hardirqs_on+0xd/0x10 [ 42.200251] do_signal+0x94/0x1ee0 [ 42.203765] ? inet_sendmsg+0x11f/0x5e0 [ 42.207710] ? inet_sendmsg+0x126/0x5e0 [ 42.211655] ? __might_sleep+0x95/0x190 [ 42.215603] ? setup_sigcontext+0x7d0/0x7d0 [ 42.219900] ? selinux_socket_sendmsg+0x36/0x40 [ 42.224540] ? security_socket_sendmsg+0x89/0xb0 [ 42.229266] ? inet_recvmsg+0x5f0/0x5f0 [ 42.233214] ? sock_sendmsg+0x4f/0x110 [ 42.237072] ? fput+0xd2/0x140 [ 42.240237] ? SYSC_sendto+0x413/0x5a0 [ 42.244097] ? SYSC_connect+0x480/0x480 [ 42.248042] ? __handle_mm_fault+0x39c0/0x39c0 [ 42.252597] ? vmacache_update+0xfe/0x130 [ 42.256720] ? exit_to_usermode_loop+0x98/0x300 [ 42.261364] exit_to_usermode_loop+0x224/0x300 [ 42.265919] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 42.271431] ? __do_page_fault+0xb60/0xb60 [ 42.275634] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.280626] syscall_return_slowpath+0x42f/0x500 [ 42.285351] ? finish_task_switch+0x1aa/0x740 [ 42.289817] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 42.294803] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 42.299704] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.304689] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.309422] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 42.314150] RIP: 0033:0x445dd9 [ 42.317311] RSP: 002b:00007f41b2a57db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 42.324993] RAX: 0000000000000005 RBX: 0000000000000000 RCX: 0000000000445dd9 [ 42.332234] RDX: 0000000000000005 RSI: 0000000020fe7000 RDI: 0000000000000003 [ 42.339475] RBP: 0000000000000000 R08: 0000000020fe7ff0 R09: 0000000000000010 [ 42.346717] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 [ 42.353966] R13: 00000000007efe8f R14: 00007f41b2a589c0 R15: 0000000000000000 [ 42.361378] Dumping ftrace buffer: [ 42.364935] (ftrace buffer empty) [ 42.368619] Kernel Offset: disabled [ 42.372225] Rebooting in 86400 seconds..