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-7,10.128.15.210' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.566516] refcount_t: underflow; use-after-free. [ 41.571571] ------------[ cut here ]------------ [ 41.576901] WARNING: CPU: 0 PID: 2983 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 41.585568] Kernel panic - not syncing: panic_on_warn set ... [ 41.585568] [ 41.592898] CPU: 0 PID: 2983 Comm: syzkaller114018 Not tainted 4.13.0-mm1+ #7 [ 41.600134] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.609452] Call Trace: [ 41.612009] dump_stack+0x194/0x257 [ 41.615607] ? arch_local_irq_restore+0x53/0x53 [ 41.620254] panic+0x1e4/0x417 [ 41.623413] ? __warn+0x1d9/0x1d9 [ 41.626835] ? show_regs_print_info+0x65/0x65 [ 41.631313] ? refcount_sub_and_test+0x167/0x1b0 [ 41.636035] __warn+0x1c4/0x1d9 [ 41.639290] ? refcount_sub_and_test+0x167/0x1b0 [ 41.644019] report_bug+0x211/0x2d0 [ 41.647625] fixup_bug+0x40/0x90 [ 41.650961] do_trap+0x260/0x390 [ 41.654301] do_error_trap+0x120/0x390 [ 41.658159] ? do_trap+0x390/0x390 [ 41.661668] ? refcount_sub_and_test+0x167/0x1b0 [ 41.666392] ? vprintk_emit+0x3ea/0x590 [ 41.670341] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.675158] do_invalid_op+0x1b/0x20 [ 41.678841] invalid_op+0x18/0x20 [ 41.682264] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 41.687590] RSP: 0018:ffff8801c033e300 EFLAGS: 00010282 [ 41.692922] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 41.700159] RDX: 0000000000000026 RSI: 1ffff10038067c20 RDI: ffffed0038067c54 [ 41.707397] RBP: ffff8801c033e390 R08: ffff8801c033d9f0 R09: 0000000000000000 [ 41.714633] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10038067c61 [ 41.721869] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce035364 [ 41.729126] ? refcount_inc+0x50/0x50 [ 41.732895] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 41.737619] ? sctp_association_free+0x2d0/0x930 [ 41.742342] ? sctp_do_sm+0x28e7/0x6dd0 [ 41.746283] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.751002] ? sctp_close+0x3c6/0x980 [ 41.754771] ? inet_release+0xed/0x1c0 [ 41.758630] sctp_wfree+0x183/0x620 [ 41.762225] ? __sctp_write_space+0x910/0x910 [ 41.766690] skb_release_head_state+0x124/0x200 [ 41.771333] skb_release_all+0x15/0x60 [ 41.775189] consume_skb+0x153/0x490 [ 41.778870] ? sctp_chunk_put+0x99/0x420 [ 41.782902] ? alloc_skb_with_frags+0x710/0x710 [ 41.787538] ? sctp_chunk_hold+0x20/0x20 [ 41.791569] ? refcount_sub_and_test+0x115/0x1b0 [ 41.796293] ? refcount_inc+0x50/0x50 [ 41.800066] ? mark_held_locks+0xb2/0x100 [ 41.804182] ? sctp_datamsg_put+0x456/0x560 [ 41.808478] sctp_chunk_put+0x29c/0x420 [ 41.812422] ? sctp_chunk_hold+0x20/0x20 [ 41.816454] ? sctp_transport_dst_confirm+0x50/0x50 [ 41.821455] sctp_chunk_free+0x53/0x60 [ 41.825312] __sctp_outq_teardown+0xc7d/0x15a0 [ 41.829862] ? inet6_release+0x50/0x70 [ 41.833724] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 41.838623] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.843792] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.848777] ? unwind_dump+0x4c0/0x4c0 [ 41.852635] ? unwind_dump+0x4c0/0x4c0 [ 41.856495] ? copy_trace+0x1d0/0x1d0 [ 41.860272] ? check_noncircular+0x20/0x20 [ 41.864475] ? check_noncircular+0x20/0x20 [ 41.868675] ? unwind_get_return_address+0x61/0xa0 [ 41.873575] ? __save_stack_trace+0x61/0xd0 [ 41.877866] ? check_noncircular+0x20/0x20 [ 41.882072] ? print_usage_bug+0x480/0x480 [ 41.886282] ? find_held_lock+0x39/0x1d0 [ 41.890323] ? lock_downgrade+0x990/0x990 [ 41.894447] ? sk_dst_check+0x560/0x560 [ 41.898393] ? rcu_read_lock_sched_held+0x108/0x120 [ 41.903381] ? lock_release+0xd70/0xd70 [ 41.907329] sctp_outq_free+0x15/0x20 [ 41.911097] sctp_association_free+0x2d0/0x930 [ 41.915650] ? sctp_asconf_queue_teardown+0x700/0x700 [ 41.920811] ? sock_def_wakeup+0x222/0x350 [ 41.925013] ? sk_dst_check+0x560/0x560 [ 41.928956] ? sctp_association_put+0x74/0x2f0 [ 41.933506] ? sctp_association_hold+0x20/0x20 [ 41.938057] ? unwind_dump+0x4c0/0x4c0 [ 41.941913] ? sctp_sm_lookup_event+0x95/0x3c0 [ 41.946465] sctp_do_sm+0x28e7/0x6dd0 [ 41.950245] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 41.956275] ? print_usage_bug+0x480/0x480 [ 41.960474] ? __lock_acquire+0x20fd/0x4620 [ 41.964768] ? print_usage_bug+0x480/0x480 [ 41.968975] ? find_held_lock+0x39/0x1d0 [ 41.973016] ? lock_downgrade+0x990/0x990 [ 41.977141] ? skb_dequeue+0x22/0x180 [ 41.980917] ? do_raw_spin_trylock+0x190/0x190 [ 41.985477] ? mark_held_locks+0xb2/0x100 [ 41.989601] ? trace_hardirqs_on+0xd/0x10 [ 41.993724] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.998278] sctp_close+0x3c6/0x980 [ 42.001879] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 42.007122] ? unwind_get_return_address+0x61/0xa0 [ 42.012024] ? check_noncircular+0x20/0x20 [ 42.016231] ? depot_save_stack+0x3b5/0x490 [ 42.020533] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 42.025000] ? ipv6_sock_mc_close+0x148/0x1a0 [ 42.029462] ? ipv6_sock_ac_drop+0x580/0x580 [ 42.033843] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.038222] ? __fsnotify_parent+0xb4/0x3a0 [ 42.042516] inet_release+0xed/0x1c0 [ 42.046201] inet6_release+0x50/0x70 [ 42.049882] sock_release+0x8d/0x1e0 [ 42.053571] ? sock_release+0x1e0/0x1e0 [ 42.057511] sock_close+0x16/0x20 [ 42.060931] __fput+0x333/0x7f0 [ 42.064184] ? fput+0x140/0x140 [ 42.067433] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.071900] ____fput+0x15/0x20 [ 42.075148] task_work_run+0x199/0x270 [ 42.079004] ? task_work_cancel+0x210/0x210 [ 42.083293] ? _raw_spin_unlock+0x22/0x30 [ 42.087408] ? switch_task_namespaces+0x87/0xc0 [ 42.092049] do_exit+0xa52/0x1b40 [ 42.095470] ? print_usage_bug+0x480/0x480 [ 42.099685] ? mm_update_next_owner+0x930/0x930 [ 42.104324] ? find_held_lock+0x39/0x1d0 [ 42.108366] ? check_noncircular+0x20/0x20 [ 42.112568] ? check_noncircular+0x20/0x20 [ 42.116772] ? lock_downgrade+0x990/0x990 [ 42.120899] ? reacquire_held_locks+0x205/0x3d0 [ 42.125534] ? check_noncircular+0x20/0x20 [ 42.129740] ? find_held_lock+0x39/0x1d0 [ 42.133780] ? lock_downgrade+0x990/0x990 [ 42.137897] ? lock_downgrade+0x990/0x990 [ 42.142016] ? find_held_lock+0x39/0x1d0 [ 42.146055] ? lock_downgrade+0x990/0x990 [ 42.150173] ? recalc_sigpending_tsk+0x117/0x150 [ 42.154897] ? recalc_sigpending+0x103/0x160 [ 42.159273] ? recalc_sigpending_tsk+0x150/0x150 [ 42.163995] ? get_signal+0x397/0x17e0 [ 42.167861] do_group_exit+0x149/0x400 [ 42.171725] ? __lock_is_held+0xbc/0x140 [ 42.175755] ? SyS_exit+0x30/0x30 [ 42.179177] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.183641] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.188631] get_signal+0x7e8/0x17e0 [ 42.192341] ? ptrace_notify+0x130/0x130 [ 42.196372] ? __local_bh_enable_ip+0x9d/0x160 [ 42.200923] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.205906] ? release_sock+0x1d4/0x2a0 [ 42.209847] ? trace_hardirqs_on+0xd/0x10 [ 42.213960] ? __local_bh_enable_ip+0x9d/0x160 [ 42.218512] ? _raw_spin_unlock_bh+0x30/0x40 [ 42.222890] ? release_sock+0x1d4/0x2a0 [ 42.226839] ? trace_hardirqs_on+0xd/0x10 [ 42.230961] do_signal+0x94/0x1ee0 [ 42.234473] ? inet_sendmsg+0x11f/0x5e0 [ 42.238411] ? inet_sendmsg+0x126/0x5e0 [ 42.242354] ? __might_sleep+0x95/0x190 [ 42.246298] ? setup_sigcontext+0x7d0/0x7d0 [ 42.250586] ? selinux_socket_sendmsg+0x36/0x40 [ 42.255223] ? security_socket_sendmsg+0x89/0xb0 [ 42.259948] ? inet_recvmsg+0x5f0/0x5f0 [ 42.263894] ? sock_sendmsg+0x4f/0x110 [ 42.267751] ? fput+0xd2/0x140 [ 42.270912] ? SYSC_sendto+0x413/0x5a0 [ 42.274771] ? SYSC_connect+0x480/0x480 [ 42.278713] ? __handle_mm_fault+0x39c0/0x39c0 [ 42.283263] ? vmacache_update+0xfe/0x130 [ 42.287384] ? exit_to_usermode_loop+0x98/0x300 [ 42.292026] exit_to_usermode_loop+0x224/0x300 [ 42.296579] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 42.302087] ? __do_page_fault+0xb60/0xb60 [ 42.306289] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.311276] syscall_return_slowpath+0x42f/0x500 [ 42.315998] ? finish_task_switch+0x1aa/0x740 [ 42.320460] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 42.325443] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 42.330341] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.335328] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.340058] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 42.344779] RIP: 0033:0x445469 [ 42.347935] RSP: 002b:00007fda9dc82db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 42.355614] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 42.362851] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 42.370087] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 42.377324] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 42.384561] R13: 00007ffc24ee20df R14: 00007fda9dc839c0 R15: 0000000000000000 [ 42.392286] Dumping ftrace buffer: [ 42.395833] (ftrace buffer empty) [ 42.399515] Kernel Offset: disabled [ 42.403126] Rebooting in 86400 seconds..