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-6,10.128.15.208' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 50.882917] refcount_t: underflow; use-after-free. [ 50.887997] ------------[ cut here ]------------ [ 50.892902] WARNING: CPU: 0 PID: 2984 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 50.901583] Kernel panic - not syncing: panic_on_warn set ... [ 50.901583] [ 50.908918] CPU: 0 PID: 2984 Comm: syzkaller475233 Not tainted 4.13.0-mm1+ #7 [ 50.916158] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 50.925484] Call Trace: [ 50.928049] dump_stack+0x194/0x257 [ 50.931648] ? arch_local_irq_restore+0x53/0x53 [ 50.936299] panic+0x1e4/0x417 [ 50.939465] ? __warn+0x1d9/0x1d9 [ 50.942889] ? show_regs_print_info+0x65/0x65 [ 50.947368] ? refcount_sub_and_test+0x167/0x1b0 [ 50.952093] __warn+0x1c4/0x1d9 [ 50.955342] ? refcount_sub_and_test+0x167/0x1b0 [ 50.960080] report_bug+0x211/0x2d0 [ 50.963684] fixup_bug+0x40/0x90 [ 50.967022] do_trap+0x260/0x390 [ 50.970367] do_error_trap+0x120/0x390 [ 50.974231] ? do_trap+0x390/0x390 [ 50.977744] ? refcount_sub_and_test+0x167/0x1b0 [ 50.982469] ? vprintk_emit+0x3ea/0x590 [ 50.986420] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 50.991238] do_invalid_op+0x1b/0x20 [ 50.994923] invalid_op+0x18/0x20 [ 50.998352] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 51.003683] RSP: 0018:ffff8801d602e300 EFLAGS: 00010282 [ 51.009019] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 51.016262] RDX: 0000000000000026 RSI: 1ffff1003ac05c20 RDI: ffffed003ac05c54 [ 51.023502] RBP: ffff8801d602e390 R08: ffff8801d602d9f0 R09: 0000000000000000 [ 51.030748] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003ac05c61 [ 51.037988] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ceb47364 [ 51.045257] ? refcount_inc+0x50/0x50 [ 51.049037] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 51.053765] ? sctp_association_free+0x2d0/0x930 [ 51.058487] ? sctp_do_sm+0x28e7/0x6dd0 [ 51.062428] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 51.067149] ? sctp_close+0x3c6/0x980 [ 51.070920] ? inet_release+0xed/0x1c0 [ 51.074811] sctp_wfree+0x183/0x620 [ 51.078428] ? __sctp_write_space+0x910/0x910 [ 51.082900] skb_release_head_state+0x124/0x200 [ 51.087542] skb_release_all+0x15/0x60 [ 51.091399] consume_skb+0x153/0x490 [ 51.095082] ? sctp_chunk_put+0x99/0x420 [ 51.099113] ? alloc_skb_with_frags+0x710/0x710 [ 51.103751] ? sctp_chunk_hold+0x20/0x20 [ 51.107800] ? refcount_sub_and_test+0x115/0x1b0 [ 51.112525] ? refcount_inc+0x50/0x50 [ 51.116293] ? mark_held_locks+0xb2/0x100 [ 51.120412] ? sctp_datamsg_put+0x456/0x560 [ 51.124716] sctp_chunk_put+0x29c/0x420 [ 51.128662] ? sctp_chunk_hold+0x20/0x20 [ 51.132698] ? sctp_transport_dst_confirm+0x50/0x50 [ 51.137701] sctp_chunk_free+0x53/0x60 [ 51.141557] __sctp_outq_teardown+0xc7d/0x15a0 [ 51.146107] ? inet6_release+0x50/0x70 [ 51.149978] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 51.154876] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.159865] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.164849] ? unwind_dump+0x4c0/0x4c0 [ 51.168706] ? unwind_dump+0x4c0/0x4c0 [ 51.172572] ? copy_trace+0x1d0/0x1d0 [ 51.176347] ? check_noncircular+0x20/0x20 [ 51.180553] ? check_noncircular+0x20/0x20 [ 51.184754] ? unwind_get_return_address+0x61/0xa0 [ 51.189652] ? __save_stack_trace+0x61/0xd0 [ 51.193949] ? check_noncircular+0x20/0x20 [ 51.198158] ? print_usage_bug+0x480/0x480 [ 51.202370] ? find_held_lock+0x39/0x1d0 [ 51.206412] ? lock_downgrade+0x990/0x990 [ 51.210538] ? sk_dst_check+0x560/0x560 [ 51.214485] ? rcu_read_lock_sched_held+0x108/0x120 [ 51.219480] ? lock_release+0xd70/0xd70 [ 51.223432] sctp_outq_free+0x15/0x20 [ 51.227205] sctp_association_free+0x2d0/0x930 [ 51.231761] ? sctp_asconf_queue_teardown+0x700/0x700 [ 51.236922] ? sock_def_wakeup+0x222/0x350 [ 51.241127] ? sk_dst_check+0x560/0x560 [ 51.245080] ? sctp_association_put+0x74/0x2f0 [ 51.249641] ? sctp_association_hold+0x20/0x20 [ 51.254205] ? unwind_dump+0x4c0/0x4c0 [ 51.258075] ? sctp_sm_lookup_event+0x95/0x3c0 [ 51.262633] sctp_do_sm+0x28e7/0x6dd0 [ 51.266419] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 51.272463] ? print_usage_bug+0x480/0x480 [ 51.276669] ? __lock_acquire+0x20fd/0x4620 [ 51.280975] ? print_usage_bug+0x480/0x480 [ 51.285191] ? find_held_lock+0x39/0x1d0 [ 51.289237] ? lock_downgrade+0x990/0x990 [ 51.293371] ? skb_dequeue+0x22/0x180 [ 51.297164] ? do_raw_spin_trylock+0x190/0x190 [ 51.301734] ? mark_held_locks+0xb2/0x100 [ 51.305865] ? trace_hardirqs_on+0xd/0x10 [ 51.309991] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 51.314548] sctp_close+0x3c6/0x980 [ 51.318154] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 51.323398] ? unwind_get_return_address+0x61/0xa0 [ 51.328311] ? check_noncircular+0x20/0x20 [ 51.332520] ? depot_save_stack+0x3b5/0x490 [ 51.336818] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 51.341285] ? ipv6_sock_mc_close+0x148/0x1a0 [ 51.345753] ? ipv6_sock_ac_drop+0x580/0x580 [ 51.350133] ? ip_mc_drop_socket+0x1ce/0x230 [ 51.354511] ? __fsnotify_parent+0xb4/0x3a0 [ 51.358804] inet_release+0xed/0x1c0 [ 51.362493] inet6_release+0x50/0x70 [ 51.366177] sock_release+0x8d/0x1e0 [ 51.369860] ? sock_release+0x1e0/0x1e0 [ 51.373809] sock_close+0x16/0x20 [ 51.377231] __fput+0x333/0x7f0 [ 51.380494] ? fput+0x140/0x140 [ 51.383754] ? _raw_spin_unlock_irq+0x27/0x70 [ 51.388232] ____fput+0x15/0x20 [ 51.391481] task_work_run+0x199/0x270 [ 51.395339] ? task_work_cancel+0x210/0x210 [ 51.399633] ? _raw_spin_unlock+0x22/0x30 [ 51.403752] ? switch_task_namespaces+0x87/0xc0 [ 51.408394] do_exit+0xa52/0x1b40 [ 51.411830] ? print_usage_bug+0x480/0x480 [ 51.416057] ? mm_update_next_owner+0x930/0x930 [ 51.420702] ? find_held_lock+0x39/0x1d0 [ 51.424736] ? check_noncircular+0x20/0x20 [ 51.428938] ? check_noncircular+0x20/0x20 [ 51.433142] ? lock_downgrade+0x990/0x990 [ 51.437270] ? reacquire_held_locks+0x205/0x3d0 [ 51.441909] ? check_noncircular+0x20/0x20 [ 51.446112] ? find_held_lock+0x39/0x1d0 [ 51.450166] ? lock_downgrade+0x990/0x990 [ 51.454285] ? lock_downgrade+0x990/0x990 [ 51.458405] ? find_held_lock+0x39/0x1d0 [ 51.462446] ? lock_downgrade+0x990/0x990 [ 51.466570] ? recalc_sigpending_tsk+0x117/0x150 [ 51.471295] ? recalc_sigpending+0x103/0x160 [ 51.475673] ? recalc_sigpending_tsk+0x150/0x150 [ 51.480394] ? get_signal+0x397/0x17e0 [ 51.484261] do_group_exit+0x149/0x400 [ 51.488120] ? __lock_is_held+0xbc/0x140 [ 51.492150] ? SyS_exit+0x30/0x30 [ 51.495574] ? _raw_spin_unlock_irq+0x27/0x70 [ 51.500042] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.505289] get_signal+0x7e8/0x17e0 [ 51.509001] ? ptrace_notify+0x130/0x130 [ 51.513034] ? __local_bh_enable_ip+0x9d/0x160 [ 51.517586] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.522577] ? release_sock+0x1d4/0x2a0 [ 51.526518] ? trace_hardirqs_on+0xd/0x10 [ 51.530631] ? __local_bh_enable_ip+0x9d/0x160 [ 51.535185] ? _raw_spin_unlock_bh+0x30/0x40 [ 51.539565] ? release_sock+0x1d4/0x2a0 [ 51.543515] ? trace_hardirqs_on+0xd/0x10 [ 51.547641] do_signal+0x94/0x1ee0 [ 51.551159] ? inet_sendmsg+0x11f/0x5e0 [ 51.555099] ? inet_sendmsg+0x126/0x5e0 [ 51.559044] ? __might_sleep+0x95/0x190 [ 51.562989] ? setup_sigcontext+0x7d0/0x7d0 [ 51.567280] ? selinux_socket_sendmsg+0x36/0x40 [ 51.571925] ? security_socket_sendmsg+0x89/0xb0 [ 51.576649] ? inet_recvmsg+0x5f0/0x5f0 [ 51.580596] ? sock_sendmsg+0x4f/0x110 [ 51.584458] ? fput+0xd2/0x140 [ 51.587623] ? SYSC_sendto+0x413/0x5a0 [ 51.591483] ? SYSC_connect+0x480/0x480 [ 51.595432] ? __handle_mm_fault+0x39c0/0x39c0 [ 51.599986] ? vmacache_update+0xfe/0x130 [ 51.604115] ? exit_to_usermode_loop+0x98/0x300 [ 51.608761] exit_to_usermode_loop+0x224/0x300 [ 51.613315] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 51.618823] ? __do_page_fault+0xb60/0xb60 [ 51.623032] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.628029] syscall_return_slowpath+0x42f/0x500 [ 51.632755] ? finish_task_switch+0x1aa/0x740 [ 51.637218] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 51.642217] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 51.647118] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.652105] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.656835] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 51.661557] RIP: 0033:0x445469 [ 51.664717] RSP: 002b:00007f2634ea5db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 51.672401] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 51.679640] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 51.686884] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 51.694126] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 51.701374] R13: 00007ffd7519fcff R14: 00007f2634ea69c0 R15: 0000000000000000 [ 51.709154] Dumping ftrace buffer: [ 51.712733] (ftrace buffer empty) [ 51.716417] Kernel Offset: disabled [ 51.720021] Rebooting in 86400 seconds..