serialport: Connected to syzkaller.us-central1-c.ci-upstream-kasan-gce-0 port 1 (session ID: d21f14a6751dffbe530e6466847bf5f3490050dcebf9e0502322bc1804a29e09, 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-0,10.128.0.54' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.688477] refcount_t: underflow; use-after-free. [ 41.689451] ------------[ cut here ]------------ [ 41.690399] WARNING: CPU: 0 PID: 2929 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 41.691594] Kernel panic - not syncing: panic_on_warn set ... [ 41.691594] [ 41.692576] CPU: 0 PID: 2929 Comm: syzkaller475625 Not tainted 4.13.0-rc3+ #22 [ 41.693551] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.694777] Call Trace: [ 41.695179] dump_stack+0x194/0x257 [ 41.695687] ? arch_local_irq_restore+0x53/0x53 [ 41.696381] panic+0x1e4/0x417 [ 41.696811] ? __warn+0x1d9/0x1d9 [ 41.697276] ? show_regs_print_info+0x65/0x65 [ 41.697885] ? refcount_sub_and_test+0x167/0x1b0 [ 41.698527] __warn+0x1c4/0x1d9 [ 41.698969] ? refcount_sub_and_test+0x167/0x1b0 [ 41.699603] report_bug+0x211/0x2d0 [ 41.700113] fixup_bug+0x40/0x90 [ 41.700567] do_trap+0x260/0x390 [ 41.701043] do_error_trap+0x120/0x390 [ 41.701567] ? do_trap+0x390/0x390 [ 41.702053] ? refcount_sub_and_test+0x167/0x1b0 [ 41.702774] ? vprintk_emit+0x3ea/0x590 [ 41.703332] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.704007] do_invalid_op+0x1b/0x20 [ 41.704516] invalid_op+0x1e/0x30 [ 41.705052] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 41.705759] RSP: 0018:ffff8801d1e86850 EFLAGS: 00010282 [ 41.706500] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 41.707451] RDX: 0000000000000026 RSI: 1ffff1003a3d0cca RDI: ffffed003a3d0cfe [ 41.708449] RBP: ffff8801d1e868e0 R08: 0000000000000001 R09: 0000000000000000 [ 41.711311] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a3d0d0b [ 41.718550] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d15c59fc [ 41.725822] ? refcount_inc+0x50/0x50 [ 41.729593] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 41.734324] ? sctp_association_free+0x2d0/0x930 [ 41.739049] ? sctp_do_sm+0x28e7/0x6d90 [ 41.742991] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.747720] ? sctp_close+0x3c6/0x980 [ 41.751491] ? inet_release+0xed/0x1c0 [ 41.755360] sctp_wfree+0x183/0x620 [ 41.758959] ? __sctp_write_space+0x910/0x910 [ 41.763427] skb_release_head_state+0x124/0x200 [ 41.768070] skb_release_all+0x15/0x60 [ 41.771927] consume_skb+0x153/0x490 [ 41.775612] ? sctp_chunk_put+0x99/0x420 [ 41.779644] ? pskb_carve+0x1db0/0x1db0 [ 41.783586] ? sctp_chunk_hold+0x20/0x20 [ 41.787619] ? refcount_sub_and_test+0x115/0x1b0 [ 41.792343] ? refcount_inc+0x50/0x50 [ 41.796113] ? mark_held_locks+0xaf/0x100 [ 41.800244] ? sctp_datamsg_put+0x456/0x560 [ 41.804543] sctp_chunk_put+0x29c/0x420 [ 41.808502] ? sctp_chunk_hold+0x20/0x20 [ 41.812536] ? sctp_transport_dst_confirm+0x50/0x50 [ 41.817533] ? noop_count+0x40/0x40 [ 41.821141] sctp_chunk_free+0x53/0x60 [ 41.824999] __sctp_outq_teardown+0xc7d/0x15a0 [ 41.829559] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 41.834458] ? lock_downgrade+0x990/0x990 [ 41.838574] ? lock_release+0xa40/0xa40 [ 41.842518] ? __free_insn_slot+0x5c0/0x5c0 [ 41.846809] ? update_stack_state+0x700/0x700 [ 41.851274] ? print_usage_bug+0x480/0x480 [ 41.855488] ? is_bpf_text_address+0xa4/0x120 [ 41.859962] ? __kernel_text_address+0xae/0xe0 [ 41.864514] ? unwind_get_return_address+0x61/0xa0 [ 41.869413] ? __save_stack_trace+0x7e/0xd0 [ 41.873708] ? check_noncircular+0x20/0x20 [ 41.877909] ? print_usage_bug+0x480/0x480 [ 41.882113] ? SOFTIRQ_verbose+0x10/0x10 [ 41.886143] ? save_stack_trace+0x16/0x20 [ 41.890262] ? save_trace+0x11f/0x350 [ 41.894044] ? lock_acquire+0x1d5/0x580 [ 41.897987] ? lock_acquire+0x1d5/0x580 [ 41.901932] ? lock_timer_base+0x1a3/0x2b0 [ 41.906146] ? find_held_lock+0x35/0x1d0 [ 41.910189] ? sock_def_wakeup+0x1f9/0x350 [ 41.914410] ? lock_downgrade+0x990/0x990 [ 41.918530] ? lock_release+0xa40/0xa40 [ 41.922481] sctp_outq_free+0x15/0x20 [ 41.926257] sctp_association_free+0x2d0/0x930 [ 41.930818] ? sctp_asconf_queue_teardown+0x700/0x700 [ 41.935990] ? sock_def_wakeup+0x222/0x350 [ 41.940217] ? sk_dst_check+0x560/0x560 [ 41.944175] ? sctp_association_put+0x74/0x2f0 [ 41.948729] ? sctp_association_hold+0x20/0x20 [ 41.953287] ? sctp_sm_lookup_event+0x95/0x3c0 [ 41.957856] sctp_do_sm+0x28e7/0x6d90 [ 41.961634] ? print_usage_bug+0x480/0x480 [ 41.965858] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 41.971924] ? print_usage_bug+0x480/0x480 [ 41.976142] ? print_usage_bug+0x480/0x480 [ 41.980349] ? lock_pin_lock+0x360/0x360 [ 41.984388] ? check_noncircular+0x20/0x20 [ 41.988596] ? check_noncircular+0x20/0x20 [ 41.992818] ? find_held_lock+0x35/0x1d0 [ 41.996854] ? skb_dequeue+0x12a/0x180 [ 42.000710] ? lock_downgrade+0x990/0x990 [ 42.004833] ? do_raw_spin_trylock+0x190/0x190 [ 42.009391] ? mark_held_locks+0xaf/0x100 [ 42.013516] ? trace_hardirqs_on+0xd/0x10 [ 42.017644] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.022203] sctp_close+0x3c6/0x980 [ 42.025812] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 42.031071] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 42.036231] ? locks_remove_file+0x414/0x560 [ 42.040612] ? fcntl_setlk+0x10c0/0x10c0 [ 42.044641] ? __fsnotify_parent+0xb4/0x3a0 [ 42.048931] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.053313] inet_release+0xed/0x1c0 [ 42.056996] sock_release+0x8d/0x1e0 [ 42.060675] ? sock_release+0x1e0/0x1e0 [ 42.064616] sock_close+0x16/0x20 [ 42.068048] __fput+0x327/0x7e0 [ 42.071317] ? fput+0x140/0x140 [ 42.074589] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 42.079754] ____fput+0x15/0x20 [ 42.083004] task_work_run+0x18a/0x260 [ 42.086861] ? task_work_cancel+0x210/0x210 [ 42.091169] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 42.096246] ? check_noncircular+0x20/0x20 [ 42.100454] get_signal+0x1440/0x17e0 [ 42.104223] ? trace_hardirqs_on+0xd/0x10 [ 42.108342] ? __local_bh_enable_ip+0x9d/0x160 [ 42.112898] ? bsearch+0x83/0xa0 [ 42.116231] ? cmp_ex_sort+0xb0/0xb0 [ 42.119920] ? search_extable+0x35/0x40 [ 42.123863] ? __get_user_4+0x1b/0x30 [ 42.127655] ? ex_handler_default+0x18/0x90 [ 42.131948] ? fixup_exception+0x93/0xc0 [ 42.135982] ? ptrace_notify+0x130/0x130 [ 42.140018] ? check_noncircular+0x20/0x20 [ 42.144236] ? pgtable_bad+0x110/0x110 [ 42.148106] ? check_noncircular+0x20/0x20 [ 42.152315] ? __bad_area_nosemaphore+0x1f4/0x3e0 [ 42.157132] ? downgrade_write+0x150/0x150 [ 42.162047] do_signal+0x94/0x1ee0 [ 42.165562] ? put_unused_fd+0x62/0x70 [ 42.169419] ? lock_downgrade+0x990/0x990 [ 42.173540] ? setup_sigcontext+0x7d0/0x7d0 [ 42.177837] ? do_raw_spin_trylock+0x190/0x190 [ 42.182390] ? __put_unused_fd+0x183/0x250 [ 42.186594] ? alloc_fdtable+0x280/0x280 [ 42.190620] ? cpumask_weight.constprop.3+0x45/0x45 [ 42.195613] ? _raw_spin_unlock+0x22/0x30 [ 42.199729] ? put_unused_fd+0x62/0x70 [ 42.203584] ? fput+0xd2/0x140 [ 42.206756] ? SYSC_accept4+0x4ec/0x850 [ 42.210700] ? is_prefetch.isra.33+0x420/0x420 [ 42.215255] ? exit_to_usermode_loop+0x98/0x2d0 [ 42.219905] exit_to_usermode_loop+0x21c/0x2d0 [ 42.224461] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 42.229967] ? exit_to_usermode_loop+0x1dc/0x2d0 [ 42.234718] syscall_return_slowpath+0x3a7/0x450 [ 42.239457] ? prepare_exit_to_usermode+0x220/0x220 [ 42.244446] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 42.249354] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.254343] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.259077] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 42.263801] RIP: 0033:0x4460d9 [ 42.266958] RSP: 002b:00007fbee04acd08 EFLAGS: 00000246 ORIG_RAX: 000000000000002b [ 42.274635] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 00000000004460d9 [ 42.281872] RDX: 0000000020ade000 RSI: 00000000201b4ff0 RDI: 0000000000000003 [ 42.289133] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fbee04ad700 [ 42.296381] R10: 00007fbee04acd10 R11: 0000000000000246 R12: 0000000000000000 [ 42.303622] R13: 00000000007efe5f R14: 00007fbee04ad9c0 R15: 0000000000000000 [ 42.311028] Dumping ftrace buffer: [ 42.314592] (ftrace buffer empty) [ 42.318273] Kernel Offset: disabled [ 42.321871] Rebooting in 86400 seconds..