serialport: Connected to syzkaller.us-central1-c.ci-upstream-kasan-gce-3 port 1 (session ID: 8f68afc1b2e45b9f14ec80ee78a9860b70f441d11a65d8009aa8c519491ecdd6, active connections: 1). 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-kasan-gce-3,10.128.0.43' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 43.240568] refcount_t: underflow; use-after-free. [ 43.241494] ------------[ cut here ]------------ [ 43.242375] WARNING: CPU: 1 PID: 2922 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 43.243622] Kernel panic - not syncing: panic_on_warn set ... [ 43.243622] [ 43.244591] CPU: 1 PID: 2922 Comm: syzkaller898555 Not tainted 4.13.0-rc3+ #21 [ 43.245553] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.246770] Call Trace: [ 43.247129] dump_stack+0x194/0x257 [ 43.247638] ? arch_local_irq_restore+0x53/0x53 [ 43.248275] panic+0x1e4/0x417 [ 43.248721] ? __warn+0x1d9/0x1d9 [ 43.249194] ? show_regs_print_info+0x65/0x65 [ 43.249808] ? refcount_sub_and_test+0x167/0x1b0 [ 43.250442] __warn+0x1c4/0x1d9 [ 43.250886] ? refcount_sub_and_test+0x167/0x1b0 [ 43.251543] report_bug+0x211/0x2d0 [ 43.252043] fixup_bug+0x40/0x90 [ 43.252504] do_trap+0x260/0x390 [ 43.252971] do_error_trap+0x120/0x390 [ 43.253512] ? do_trap+0x390/0x390 [ 43.253990] ? refcount_sub_and_test+0x167/0x1b0 [ 43.254693] ? vprintk_emit+0x3ea/0x590 [ 43.255266] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.255930] do_invalid_op+0x1b/0x20 [ 43.256433] invalid_op+0x1e/0x30 [ 43.256923] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 43.257636] RSP: 0018:ffff8801d2646330 EFLAGS: 00010286 [ 43.258365] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 43.259323] RDX: 0000000000000026 RSI: 1ffff1003a4c8c26 RDI: ffffed003a4c8c5a [ 43.260283] RBP: ffff8801d26463c0 R08: 0000000000000001 R09: 0000000000000000 [ 43.264161] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a4c8c67 [ 43.271405] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d195d9fc [ 43.278689] ? refcount_inc+0x50/0x50 [ 43.282472] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 43.287205] ? sctp_association_free+0x2d0/0x930 [ 43.291941] ? sctp_do_sm+0x28e7/0x6d90 [ 43.295893] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 43.300626] ? sctp_close+0x3c6/0x980 [ 43.304399] ? inet_release+0xed/0x1c0 [ 43.308266] sctp_wfree+0x183/0x620 [ 43.311867] ? __sctp_write_space+0x910/0x910 [ 43.316342] skb_release_head_state+0x124/0x200 [ 43.320992] skb_release_all+0x15/0x60 [ 43.324853] consume_skb+0x153/0x490 [ 43.328539] ? sctp_chunk_put+0x99/0x420 [ 43.332572] ? pskb_carve+0x1db0/0x1db0 [ 43.336517] ? sctp_chunk_hold+0x20/0x20 [ 43.340553] ? refcount_sub_and_test+0x115/0x1b0 [ 43.345281] ? refcount_inc+0x50/0x50 [ 43.349047] ? mark_held_locks+0xaf/0x100 [ 43.353169] ? sctp_datamsg_put+0x456/0x560 [ 43.357464] sctp_chunk_put+0x29c/0x420 [ 43.361407] ? sctp_chunk_hold+0x20/0x20 [ 43.365439] ? sctp_transport_dst_confirm+0x50/0x50 [ 43.370428] ? noop_count+0x40/0x40 [ 43.374029] sctp_chunk_free+0x53/0x60 [ 43.377890] __sctp_outq_teardown+0xc7d/0x15a0 [ 43.382448] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 43.387353] ? lock_downgrade+0x990/0x990 [ 43.391470] ? lock_release+0xa40/0xa40 [ 43.395417] ? __free_insn_slot+0x5c0/0x5c0 [ 43.399707] ? update_stack_state+0x700/0x700 [ 43.404169] ? print_usage_bug+0x480/0x480 [ 43.408379] ? is_bpf_text_address+0xa4/0x120 [ 43.412848] ? __kernel_text_address+0xae/0xe0 [ 43.417407] ? unwind_get_return_address+0x61/0xa0 [ 43.422656] ? __save_stack_trace+0x7e/0xd0 [ 43.426960] ? check_noncircular+0x20/0x20 [ 43.431164] ? print_usage_bug+0x480/0x480 [ 43.435376] ? SOFTIRQ_verbose+0x10/0x10 [ 43.439403] ? save_stack_trace+0x16/0x20 [ 43.443526] ? save_trace+0x11f/0x350 [ 43.447301] ? lock_acquire+0x1d5/0x580 [ 43.451240] ? lock_acquire+0x1d5/0x580 [ 43.455183] ? lock_timer_base+0x1a3/0x2b0 [ 43.459390] ? find_held_lock+0x35/0x1d0 [ 43.463427] ? sock_def_wakeup+0x1f9/0x350 [ 43.467630] ? lock_downgrade+0x990/0x990 [ 43.471753] ? lock_release+0xa40/0xa40 [ 43.475704] sctp_outq_free+0x15/0x20 [ 43.479474] sctp_association_free+0x2d0/0x930 [ 43.484032] ? sctp_asconf_queue_teardown+0x700/0x700 [ 43.489192] ? sock_def_wakeup+0x222/0x350 [ 43.493394] ? sk_dst_check+0x560/0x560 [ 43.497338] ? sctp_association_put+0x74/0x2f0 [ 43.501884] ? sctp_association_hold+0x20/0x20 [ 43.506433] ? print_usage_bug+0x480/0x480 [ 43.510631] ? find_held_lock+0x35/0x1d0 [ 43.514656] ? sctp_sm_lookup_event+0x95/0x3c0 [ 43.519207] sctp_do_sm+0x28e7/0x6d90 [ 43.522984] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 43.529011] ? print_usage_bug+0x480/0x480 [ 43.533214] ? print_usage_bug+0x480/0x480 [ 43.537428] ? find_held_lock+0x35/0x1d0 [ 43.541462] ? skb_dequeue+0x12a/0x180 [ 43.545316] ? lock_downgrade+0x990/0x990 [ 43.549434] ? do_raw_spin_trylock+0x190/0x190 [ 43.553992] ? mark_held_locks+0xaf/0x100 [ 43.558114] ? trace_hardirqs_on+0xd/0x10 [ 43.562240] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 43.566791] sctp_close+0x3c6/0x980 [ 43.570390] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 43.575636] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.580619] ? trace_hardirqs_on+0xd/0x10 [ 43.584742] ? rcu_idle_enter+0x1a0/0x1a0 [ 43.588859] ? locks_remove_file+0x414/0x560 [ 43.593235] ? fcntl_setlk+0x10c0/0x10c0 [ 43.597262] ? find_held_lock+0x35/0x1d0 [ 43.601292] ? __fsnotify_parent+0xb4/0x3a0 [ 43.605582] ? ip_mc_drop_socket+0x1ce/0x230 [ 43.609965] inet_release+0xed/0x1c0 [ 43.613663] sock_release+0x8d/0x1e0 [ 43.617360] ? sock_release+0x1e0/0x1e0 [ 43.621300] sock_close+0x16/0x20 [ 43.625070] __fput+0x327/0x7e0 [ 43.628323] ? fput+0x140/0x140 [ 43.631575] ? check_same_owner+0x320/0x320 [ 43.635872] ____fput+0x15/0x20 [ 43.639122] task_work_run+0x18a/0x260 [ 43.642980] ? task_work_cancel+0x210/0x210 [ 43.647267] ? free_nsproxy+0x185/0x1f0 [ 43.651296] ? switch_task_namespaces+0xa2/0xc0 [ 43.655937] do_exit+0xa32/0x1b10 [ 43.659359] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 43.664524] ? page_add_new_anon_rmap+0x36c/0x750 [ 43.669349] ? exit_notify+0xb10/0xb10 [ 43.673215] ? do_huge_pmd_anonymous_page+0xa32/0x1890 [ 43.678464] ? lock_downgrade+0x990/0x990 [ 43.682587] ? pudp_huge_clear_flush+0x1f0/0x1f0 [ 43.687314] ? do_raw_spin_trylock+0x190/0x190 [ 43.691875] ? __lock_acquire+0x6ef/0x3dc0 [ 43.696085] ? _raw_spin_unlock+0x22/0x30 [ 43.700213] ? do_huge_pmd_anonymous_page+0xa9a/0x1890 [ 43.705475] ? check_noncircular+0x20/0x20 [ 43.709693] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 43.714858] ? find_held_lock+0x35/0x1d0 [ 43.718894] ? get_signal+0x855/0x17e0 [ 43.722750] ? lock_downgrade+0x990/0x990 [ 43.726879] do_group_exit+0x149/0x400 [ 43.730743] ? __lock_is_held+0xb6/0x140 [ 43.734778] ? SyS_exit+0x30/0x30 [ 43.738206] ? _raw_spin_unlock_irq+0x27/0x70 [ 43.742679] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.747674] get_signal+0x7e8/0x17e0 [ 43.751386] ? ptrace_notify+0x130/0x130 [ 43.755423] ? __fd_install+0x2da/0x6a0 [ 43.759368] ? lock_downgrade+0x990/0x990 [ 43.763494] ? __lock_is_held+0xb6/0x140 [ 43.767536] do_signal+0x94/0x1ee0 [ 43.771050] ? __fd_install+0x2f7/0x6a0 [ 43.774994] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 43.779736] ? get_unused_fd_flags+0x190/0x190 [ 43.784295] ? setup_sigcontext+0x7d0/0x7d0 [ 43.788608] ? copy_user_generic_unrolled+0x89/0xc0 [ 43.793605] ? _copy_to_user+0xa2/0xc0 [ 43.797472] ? fd_install+0x4d/0x60 [ 43.801071] ? fput+0xd2/0x140 [ 43.804241] ? SYSC_accept4+0x4ec/0x850 [ 43.808193] ? exit_to_usermode_loop+0x98/0x2d0 [ 43.812853] exit_to_usermode_loop+0x21c/0x2d0 [ 43.817422] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 43.822977] ? __do_page_fault+0x2b8/0xb60 [ 43.827193] syscall_return_slowpath+0x3a7/0x450 [ 43.832332] ? prepare_exit_to_usermode+0x220/0x220 [ 43.837334] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 43.842239] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.847237] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 43.851978] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 43.856704] RIP: 0033:0x445d69 [ 43.859866] RSP: 002b:00007f7931e04dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 43.867545] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000445d69 [ 43.874791] RDX: 0000000020ade000 RSI: 00000000201b4ff0 RDI: 0000000000000003 [ 43.882035] RBP: 0000000000000000 R08: 00007f7931e05700 R09: 00007f7931e05700 [ 43.889279] R10: 00007f7931e05700 R11: 0000000000000202 R12: 0000000000000000 [ 43.896522] R13: 00000000007efe6f R14: 00007f7931e059c0 R15: 0000000000000000 [ 43.904178] Dumping ftrace buffer: [ 43.907782] (ftrace buffer empty) [ 43.911467] Kernel Offset: disabled [ 43.915068] Rebooting in 86400 seconds..