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-1,10.128.0.4' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 44.901790] refcount_t: underflow; use-after-free. [ 44.906908] ------------[ cut here ]------------ [ 44.911864] WARNING: CPU: 1 PID: 2984 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 44.920558] Kernel panic - not syncing: panic_on_warn set ... [ 44.920558] [ 44.927895] CPU: 1 PID: 2984 Comm: syzkaller058840 Not tainted 4.13.0-mm1+ #7 [ 44.935136] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 44.944467] Call Trace: [ 44.947030] dump_stack+0x194/0x257 [ 44.950631] ? arch_local_irq_restore+0x53/0x53 [ 44.955282] panic+0x1e4/0x417 [ 44.958445] ? __warn+0x1d9/0x1d9 [ 44.961869] ? show_regs_print_info+0x65/0x65 [ 44.966356] ? refcount_sub_and_test+0x167/0x1b0 [ 44.971081] __warn+0x1c4/0x1d9 [ 44.974330] ? refcount_sub_and_test+0x167/0x1b0 [ 44.979057] report_bug+0x211/0x2d0 [ 44.982661] fixup_bug+0x40/0x90 [ 44.985997] do_trap+0x260/0x390 [ 44.989340] do_error_trap+0x120/0x390 [ 44.993202] ? do_trap+0x390/0x390 [ 44.996713] ? refcount_sub_and_test+0x167/0x1b0 [ 45.001437] ? vprintk_emit+0x3ea/0x590 [ 45.005393] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 45.010211] do_invalid_op+0x1b/0x20 [ 45.013893] invalid_op+0x18/0x20 [ 45.017315] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 45.022644] RSP: 0018:ffff8801ceade300 EFLAGS: 00010282 [ 45.027982] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 45.035222] RDX: 0000000000000026 RSI: 1ffff10039d5bc20 RDI: ffffed0039d5bc54 [ 45.042466] RBP: ffff8801ceade390 R08: ffff8801ceadd9f0 R09: 0000000000000000 [ 45.049714] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039d5bc61 [ 45.056956] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d28beae4 [ 45.064218] ? refcount_inc+0x50/0x50 [ 45.067990] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 45.072717] ? sctp_association_free+0x2d0/0x930 [ 45.077444] ? sctp_do_sm+0x28e7/0x6dd0 [ 45.081393] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 45.086127] ? sctp_close+0x3c6/0x980 [ 45.089897] ? inet_release+0xed/0x1c0 [ 45.093763] sctp_wfree+0x183/0x620 [ 45.097361] ? __sctp_write_space+0x910/0x910 [ 45.101829] skb_release_head_state+0x124/0x200 [ 45.106468] skb_release_all+0x15/0x60 [ 45.110324] consume_skb+0x153/0x490 [ 45.114013] ? sctp_chunk_put+0x99/0x420 [ 45.118044] ? alloc_skb_with_frags+0x710/0x710 [ 45.122684] ? sctp_chunk_hold+0x20/0x20 [ 45.126717] ? refcount_sub_and_test+0x115/0x1b0 [ 45.131445] ? refcount_inc+0x50/0x50 [ 45.135216] ? mark_held_locks+0xb2/0x100 [ 45.139335] ? sctp_datamsg_put+0x456/0x560 [ 45.143639] sctp_chunk_put+0x29c/0x420 [ 45.147588] ? sctp_chunk_hold+0x20/0x20 [ 45.151623] ? sctp_transport_dst_confirm+0x50/0x50 [ 45.156627] sctp_chunk_free+0x53/0x60 [ 45.160486] __sctp_outq_teardown+0xc7d/0x15a0 [ 45.165039] ? inet6_release+0x50/0x70 [ 45.168903] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 45.173803] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 45.178792] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 45.183779] ? unwind_dump+0x4c0/0x4c0 [ 45.187638] ? unwind_dump+0x4c0/0x4c0 [ 45.191500] ? copy_trace+0x1d0/0x1d0 [ 45.195277] ? check_noncircular+0x20/0x20 [ 45.199485] ? check_noncircular+0x20/0x20 [ 45.203688] ? unwind_get_return_address+0x61/0xa0 [ 45.208586] ? __save_stack_trace+0x61/0xd0 [ 45.212879] ? check_noncircular+0x20/0x20 [ 45.217099] ? print_usage_bug+0x480/0x480 [ 45.221313] ? find_held_lock+0x39/0x1d0 [ 45.225354] ? lock_downgrade+0x990/0x990 [ 45.229484] ? sk_dst_check+0x560/0x560 [ 45.233429] ? rcu_read_lock_sched_held+0x108/0x120 [ 45.238424] ? lock_release+0xd70/0xd70 [ 45.242378] sctp_outq_free+0x15/0x20 [ 45.246148] sctp_association_free+0x2d0/0x930 [ 45.250703] ? sctp_asconf_queue_teardown+0x700/0x700 [ 45.255862] ? sock_def_wakeup+0x222/0x350 [ 45.260067] ? sk_dst_check+0x560/0x560 [ 45.264013] ? sctp_association_put+0x74/0x2f0 [ 45.268564] ? sctp_association_hold+0x20/0x20 [ 45.273116] ? unwind_dump+0x4c0/0x4c0 [ 45.276977] ? sctp_sm_lookup_event+0x95/0x3c0 [ 45.281532] sctp_do_sm+0x28e7/0x6dd0 [ 45.285315] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 45.291347] ? print_usage_bug+0x480/0x480 [ 45.295551] ? __lock_acquire+0x20fd/0x4620 [ 45.299846] ? print_usage_bug+0x480/0x480 [ 45.304055] ? find_held_lock+0x39/0x1d0 [ 45.308096] ? lock_downgrade+0x990/0x990 [ 45.312222] ? skb_dequeue+0x22/0x180 [ 45.316000] ? do_raw_spin_trylock+0x190/0x190 [ 45.320559] ? mark_held_locks+0xb2/0x100 [ 45.324684] ? trace_hardirqs_on+0xd/0x10 [ 45.328810] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 45.333383] sctp_close+0x3c6/0x980 [ 45.336988] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 45.342233] ? unwind_get_return_address+0x61/0xa0 [ 45.347135] ? check_noncircular+0x20/0x20 [ 45.351345] ? depot_save_stack+0x3b5/0x490 [ 45.355645] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 45.360113] ? ipv6_sock_mc_close+0x148/0x1a0 [ 45.364577] ? ipv6_sock_ac_drop+0x580/0x580 [ 45.368954] ? ip_mc_drop_socket+0x1ce/0x230 [ 45.373332] ? __fsnotify_parent+0xb4/0x3a0 [ 45.377625] inet_release+0xed/0x1c0 [ 45.381315] inet6_release+0x50/0x70 [ 45.385000] sock_release+0x8d/0x1e0 [ 45.388693] ? sock_release+0x1e0/0x1e0 [ 45.392636] sock_close+0x16/0x20 [ 45.396061] __fput+0x333/0x7f0 [ 45.399316] ? fput+0x140/0x140 [ 45.402572] ? _raw_spin_unlock_irq+0x27/0x70 [ 45.407041] ____fput+0x15/0x20 [ 45.410295] task_work_run+0x199/0x270 [ 45.414164] ? task_work_cancel+0x210/0x210 [ 45.418458] ? _raw_spin_unlock+0x22/0x30 [ 45.422577] ? switch_task_namespaces+0x87/0xc0 [ 45.427223] do_exit+0xa52/0x1b40 [ 45.430663] ? print_usage_bug+0x480/0x480 [ 45.434883] ? mm_update_next_owner+0x930/0x930 [ 45.439539] ? find_held_lock+0x39/0x1d0 [ 45.443578] ? check_noncircular+0x20/0x20 [ 45.447786] ? check_noncircular+0x20/0x20 [ 45.451995] ? lock_downgrade+0x990/0x990 [ 45.456155] ? reacquire_held_locks+0x205/0x3d0 [ 45.460796] ? check_noncircular+0x20/0x20 [ 45.465001] ? find_held_lock+0x39/0x1d0 [ 45.469058] ? lock_downgrade+0x990/0x990 [ 45.473178] ? lock_downgrade+0x990/0x990 [ 45.477300] ? find_held_lock+0x39/0x1d0 [ 45.481345] ? lock_downgrade+0x990/0x990 [ 45.485477] ? recalc_sigpending_tsk+0x117/0x150 [ 45.490206] ? recalc_sigpending+0x103/0x160 [ 45.494587] ? recalc_sigpending_tsk+0x150/0x150 [ 45.499314] ? get_signal+0x397/0x17e0 [ 45.503184] do_group_exit+0x149/0x400 [ 45.507043] ? __lock_is_held+0xbc/0x140 [ 45.511084] ? SyS_exit+0x30/0x30 [ 45.514518] ? _raw_spin_unlock_irq+0x27/0x70 [ 45.518984] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.523973] get_signal+0x7e8/0x17e0 [ 45.527685] ? ptrace_notify+0x130/0x130 [ 45.531718] ? __local_bh_enable_ip+0x9d/0x160 [ 45.536270] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.541255] ? release_sock+0x1d4/0x2a0 [ 45.545198] ? trace_hardirqs_on+0xd/0x10 [ 45.549314] ? __local_bh_enable_ip+0x9d/0x160 [ 45.553865] ? _raw_spin_unlock_bh+0x30/0x40 [ 45.558243] ? release_sock+0x1d4/0x2a0 [ 45.562192] ? trace_hardirqs_on+0xd/0x10 [ 45.566331] do_signal+0x94/0x1ee0 [ 45.569853] ? inet_sendmsg+0x11f/0x5e0 [ 45.573795] ? inet_sendmsg+0x126/0x5e0 [ 45.577739] ? __might_sleep+0x95/0x190 [ 45.581686] ? setup_sigcontext+0x7d0/0x7d0 [ 45.585979] ? selinux_socket_sendmsg+0x36/0x40 [ 45.590616] ? security_socket_sendmsg+0x89/0xb0 [ 45.595351] ? inet_recvmsg+0x5f0/0x5f0 [ 45.599298] ? sock_sendmsg+0x4f/0x110 [ 45.603153] ? fput+0xd2/0x140 [ 45.606334] ? SYSC_sendto+0x413/0x5a0 [ 45.610196] ? SYSC_connect+0x480/0x480 [ 45.614139] ? __handle_mm_fault+0x39c0/0x39c0 [ 45.618692] ? vmacache_update+0xfe/0x130 [ 45.623199] ? exit_to_usermode_loop+0x98/0x300 [ 45.627845] exit_to_usermode_loop+0x224/0x300 [ 45.632400] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 45.637910] ? __do_page_fault+0xb60/0xb60 [ 45.642113] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.647102] syscall_return_slowpath+0x42f/0x500 [ 45.651826] ? finish_task_switch+0x1aa/0x740 [ 45.656291] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 45.661281] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 45.666182] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 45.671173] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 45.675906] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 45.680631] RIP: 0033:0x445469 [ 45.683790] RSP: 002b:00007f76a0be5db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 45.691469] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 45.698707] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 45.705945] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 45.713183] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 45.720421] R13: 00007ffeaf85862f R14: 00007f76a0be69c0 R15: 0000000000000000 [ 45.727899] Dumping ftrace buffer: [ 45.731465] (ftrace buffer empty) [ 45.735148] Kernel Offset: disabled [ 45.738767] Rebooting in 86400 seconds..