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-7,10.128.0.9' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 43.654110] refcount_t: underflow; use-after-free. [ 43.659179] ------------[ cut here ]------------ [ 43.664132] WARNING: CPU: 0 PID: 2987 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 43.672832] Kernel panic - not syncing: panic_on_warn set ... [ 43.672832] [ 43.680166] CPU: 0 PID: 2987 Comm: syzkaller488765 Not tainted 4.13.0-mm1+ #7 [ 43.687406] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.696802] Call Trace: [ 43.699402] dump_stack+0x194/0x257 [ 43.703004] ? arch_local_irq_restore+0x53/0x53 [ 43.707654] panic+0x1e4/0x417 [ 43.710817] ? __warn+0x1d9/0x1d9 [ 43.714238] ? show_regs_print_info+0x65/0x65 [ 43.718715] ? refcount_sub_and_test+0x167/0x1b0 [ 43.723438] __warn+0x1c4/0x1d9 [ 43.726687] ? refcount_sub_and_test+0x167/0x1b0 [ 43.731413] report_bug+0x211/0x2d0 [ 43.735016] fixup_bug+0x40/0x90 [ 43.738352] do_trap+0x260/0x390 [ 43.741692] do_error_trap+0x120/0x390 [ 43.745553] ? do_trap+0x390/0x390 [ 43.749063] ? refcount_sub_and_test+0x167/0x1b0 [ 43.753785] ? vprintk_emit+0x3ea/0x590 [ 43.757735] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.762552] do_invalid_op+0x1b/0x20 [ 43.766233] invalid_op+0x18/0x20 [ 43.769657] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 43.774988] RSP: 0018:ffff8801ce7be300 EFLAGS: 00010282 [ 43.780321] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 43.787559] RDX: 0000000000000026 RSI: 1ffff10039cf7c20 RDI: ffffed0039cf7c54 [ 43.794801] RBP: ffff8801ce7be390 R08: ffff8801ce7bd9f0 R09: 0000000000000000 [ 43.802038] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039cf7c61 [ 43.809278] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce04d364 [ 43.816541] ? refcount_inc+0x50/0x50 [ 43.820313] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 43.825042] ? sctp_association_free+0x2d0/0x930 [ 43.829765] ? sctp_do_sm+0x28e7/0x6dd0 [ 43.833706] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 43.838430] ? sctp_close+0x3c6/0x980 [ 43.842199] ? inet_release+0xed/0x1c0 [ 43.846059] sctp_wfree+0x183/0x620 [ 43.849656] ? __sctp_write_space+0x910/0x910 [ 43.854123] skb_release_head_state+0x124/0x200 [ 43.858764] skb_release_all+0x15/0x60 [ 43.862621] consume_skb+0x153/0x490 [ 43.866302] ? sctp_chunk_put+0x99/0x420 [ 43.870333] ? alloc_skb_with_frags+0x710/0x710 [ 43.874982] ? sctp_chunk_hold+0x20/0x20 [ 43.879018] ? refcount_sub_and_test+0x115/0x1b0 [ 43.883741] ? refcount_inc+0x50/0x50 [ 43.887511] ? mark_held_locks+0xb2/0x100 [ 43.891630] ? sctp_datamsg_put+0x456/0x560 [ 43.895928] sctp_chunk_put+0x29c/0x420 [ 43.899876] ? sctp_chunk_hold+0x20/0x20 [ 43.903911] ? sctp_transport_dst_confirm+0x50/0x50 [ 43.908912] sctp_chunk_free+0x53/0x60 [ 43.912770] __sctp_outq_teardown+0xc7d/0x15a0 [ 43.917321] ? inet6_release+0x50/0x70 [ 43.921183] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 43.926081] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 43.931071] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 43.936057] ? unwind_dump+0x4c0/0x4c0 [ 43.939915] ? unwind_dump+0x4c0/0x4c0 [ 43.943777] ? copy_trace+0x1d0/0x1d0 [ 43.947553] ? check_noncircular+0x20/0x20 [ 43.951756] ? check_noncircular+0x20/0x20 [ 43.955958] ? unwind_get_return_address+0x61/0xa0 [ 43.960859] ? __save_stack_trace+0x61/0xd0 [ 43.965157] ? check_noncircular+0x20/0x20 [ 43.969369] ? print_usage_bug+0x480/0x480 [ 43.973582] ? find_held_lock+0x39/0x1d0 [ 43.977623] ? lock_downgrade+0x990/0x990 [ 43.981746] ? sk_dst_check+0x560/0x560 [ 43.985692] ? rcu_read_lock_sched_held+0x108/0x120 [ 43.991013] ? lock_release+0xd70/0xd70 [ 43.994967] sctp_outq_free+0x15/0x20 [ 43.998737] sctp_association_free+0x2d0/0x930 [ 44.003299] ? sctp_asconf_queue_teardown+0x700/0x700 [ 44.008464] ? sock_def_wakeup+0x222/0x350 [ 44.012670] ? sk_dst_check+0x560/0x560 [ 44.016618] ? sctp_association_put+0x74/0x2f0 [ 44.021175] ? sctp_association_hold+0x20/0x20 [ 44.025728] ? unwind_dump+0x4c0/0x4c0 [ 44.029590] ? sctp_sm_lookup_event+0x95/0x3c0 [ 44.034148] sctp_do_sm+0x28e7/0x6dd0 [ 44.037931] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 44.043965] ? print_usage_bug+0x480/0x480 [ 44.048169] ? __lock_acquire+0x20fd/0x4620 [ 44.052462] ? print_usage_bug+0x480/0x480 [ 44.056670] ? find_held_lock+0x39/0x1d0 [ 44.060714] ? lock_downgrade+0x990/0x990 [ 44.064830] ? mark_held_locks+0xb2/0x100 [ 44.068951] ? skb_dequeue+0x22/0x180 [ 44.072725] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 44.077454] ? do_raw_spin_trylock+0x190/0x190 [ 44.082012] ? mark_held_locks+0xb2/0x100 [ 44.086142] ? trace_hardirqs_on+0xd/0x10 [ 44.090268] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 44.094824] sctp_close+0x3c6/0x980 [ 44.098431] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 44.103677] ? unwind_get_return_address+0x61/0xa0 [ 44.108580] ? check_noncircular+0x20/0x20 [ 44.112789] ? depot_save_stack+0x3b5/0x490 [ 44.117087] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 44.121564] ? ipv6_sock_mc_close+0x148/0x1a0 [ 44.126028] ? ipv6_sock_ac_drop+0x580/0x580 [ 44.130691] ? ip_mc_drop_socket+0x1ce/0x230 [ 44.135138] ? __fsnotify_parent+0xb4/0x3a0 [ 44.139437] inet_release+0xed/0x1c0 [ 44.143125] inet6_release+0x50/0x70 [ 44.146813] sock_release+0x8d/0x1e0 [ 44.150500] ? sock_release+0x1e0/0x1e0 [ 44.154447] sock_close+0x16/0x20 [ 44.157873] __fput+0x333/0x7f0 [ 44.161128] ? fput+0x140/0x140 [ 44.164382] ? _raw_spin_unlock_irq+0x27/0x70 [ 44.168856] ____fput+0x15/0x20 [ 44.172110] task_work_run+0x199/0x270 [ 44.175970] ? task_work_cancel+0x210/0x210 [ 44.180263] ? _raw_spin_unlock+0x22/0x30 [ 44.184382] ? switch_task_namespaces+0x87/0xc0 [ 44.189025] do_exit+0xa52/0x1b40 [ 44.192452] ? print_usage_bug+0x480/0x480 [ 44.196670] ? mm_update_next_owner+0x930/0x930 [ 44.201308] ? find_held_lock+0x39/0x1d0 [ 44.205342] ? check_noncircular+0x20/0x20 [ 44.209545] ? check_noncircular+0x20/0x20 [ 44.213747] ? lock_downgrade+0x990/0x990 [ 44.217877] ? reacquire_held_locks+0x205/0x3d0 [ 44.222513] ? check_noncircular+0x20/0x20 [ 44.226717] ? find_held_lock+0x39/0x1d0 [ 44.230757] ? lock_downgrade+0x990/0x990 [ 44.234874] ? lock_downgrade+0x990/0x990 [ 44.238992] ? find_held_lock+0x39/0x1d0 [ 44.243032] ? lock_downgrade+0x990/0x990 [ 44.247149] ? recalc_sigpending_tsk+0x117/0x150 [ 44.251876] ? recalc_sigpending+0x103/0x160 [ 44.256251] ? recalc_sigpending_tsk+0x150/0x150 [ 44.260981] ? get_signal+0x397/0x17e0 [ 44.264851] do_group_exit+0x149/0x400 [ 44.268706] ? __lock_is_held+0xbc/0x140 [ 44.272738] ? SyS_exit+0x30/0x30 [ 44.276160] ? _raw_spin_unlock_irq+0x27/0x70 [ 44.280625] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 44.285613] get_signal+0x7e8/0x17e0 [ 44.289324] ? ptrace_notify+0x130/0x130 [ 44.293356] ? __local_bh_enable_ip+0x9d/0x160 [ 44.297996] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 44.302983] ? release_sock+0x1d4/0x2a0 [ 44.306925] ? trace_hardirqs_on+0xd/0x10 [ 44.311041] ? __local_bh_enable_ip+0x9d/0x160 [ 44.315596] ? _raw_spin_unlock_bh+0x30/0x40 [ 44.319975] ? release_sock+0x1d4/0x2a0 [ 44.323923] ? trace_hardirqs_on+0xd/0x10 [ 44.328048] do_signal+0x94/0x1ee0 [ 44.331562] ? inet_sendmsg+0x11f/0x5e0 [ 44.335506] ? inet_sendmsg+0x126/0x5e0 [ 44.339451] ? __might_sleep+0x95/0x190 [ 44.343398] ? setup_sigcontext+0x7d0/0x7d0 [ 44.347689] ? selinux_socket_sendmsg+0x36/0x40 [ 44.352324] ? security_socket_sendmsg+0x89/0xb0 [ 44.357048] ? inet_recvmsg+0x5f0/0x5f0 [ 44.360996] ? sock_sendmsg+0x4f/0x110 [ 44.364853] ? fput+0xd2/0x140 [ 44.368013] ? SYSC_sendto+0x413/0x5a0 [ 44.371875] ? SYSC_connect+0x480/0x480 [ 44.375815] ? __handle_mm_fault+0x39c0/0x39c0 [ 44.380365] ? vmacache_update+0xfe/0x130 [ 44.384486] ? exit_to_usermode_loop+0x98/0x300 [ 44.389127] exit_to_usermode_loop+0x224/0x300 [ 44.393680] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 44.399187] ? __do_page_fault+0xb60/0xb60 [ 44.403392] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 44.408383] syscall_return_slowpath+0x42f/0x500 [ 44.413105] ? finish_task_switch+0x1aa/0x740 [ 44.417570] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 44.422556] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 44.427458] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 44.432442] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 44.437174] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 44.441895] RIP: 0033:0x445469 [ 44.445052] RSP: 002b:00007f4aa00b9db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 44.452730] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 44.459970] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 44.467207] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 44.474444] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 44.481681] R13: 00007ffd9e18463f R14: 00007f4aa00ba9c0 R15: 0000000000000000 [ 44.489482] Dumping ftrace buffer: [ 44.493050] (ftrace buffer empty) [ 44.496731] Kernel Offset: disabled [ 44.500336] Rebooting in 86400 seconds..