serialport: Connected to syzkaller.us-central1-c.ci-upstream-kasan-gce-8 port 1 (session ID: 0be9d1a808b2173401592382e5f4dfd9f20aefca7c0fa7a6b8332289238ac7e0, 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-8,10.128.0.47' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 43.225622] refcount_t: underflow; use-after-free. [ 43.226480] ------------[ cut here ]------------ [ 43.227319] WARNING: CPU: 0 PID: 2912 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 43.228522] Kernel panic - not syncing: panic_on_warn set ... [ 43.228522] [ 43.229521] CPU: 0 PID: 2912 Comm: syzkaller954174 Not tainted 4.13.0-rc3+ #20 [ 43.230485] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 43.231731] Call Trace: [ 43.232108] dump_stack+0x194/0x257 [ 43.232599] ? arch_local_irq_restore+0x53/0x53 [ 43.233300] panic+0x1e4/0x417 [ 43.233733] ? __warn+0x1d9/0x1d9 [ 43.234199] ? show_regs_print_info+0x65/0x65 [ 43.234828] ? refcount_sub_and_test+0x167/0x1b0 [ 43.235545] __warn+0x1c4/0x1d9 [ 43.235989] ? refcount_sub_and_test+0x167/0x1b0 [ 43.236624] report_bug+0x211/0x2d0 [ 43.237119] fixup_bug+0x40/0x90 [ 43.237611] do_trap+0x260/0x390 [ 43.238073] do_error_trap+0x120/0x390 [ 43.238614] ? do_trap+0x390/0x390 [ 43.239104] ? refcount_sub_and_test+0x167/0x1b0 [ 43.239736] ? vprintk_emit+0x3ea/0x590 [ 43.240295] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 43.240947] do_invalid_op+0x1b/0x20 [ 43.241449] invalid_op+0x1e/0x30 [ 43.241915] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 43.242635] RSP: 0018:ffff8801d1cd6850 EFLAGS: 00010282 [ 43.243385] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 43.244360] RDX: 0000000000000026 RSI: 1ffff1003a39acca RDI: ffffed003a39acfe [ 43.245346] RBP: ffff8801d1cd68e0 R08: 0000000000000001 R09: 0000000000000000 [ 43.249957] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a39ad0b [ 43.257195] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d34309fc [ 43.264459] ? refcount_inc+0x50/0x50 [ 43.268229] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 43.272951] ? sctp_association_free+0x2d0/0x930 [ 43.277670] ? sctp_do_sm+0x28e7/0x6d90 [ 43.281614] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 43.286338] ? sctp_close+0x3c6/0x980 [ 43.290104] ? inet_release+0xed/0x1c0 [ 43.293962] sctp_wfree+0x183/0x620 [ 43.297557] ? __sctp_write_space+0x910/0x910 [ 43.302021] skb_release_head_state+0x124/0x200 [ 43.306657] skb_release_all+0x15/0x60 [ 43.310513] consume_skb+0x153/0x490 [ 43.314191] ? sctp_chunk_put+0x99/0x420 [ 43.318222] ? pskb_carve+0x1db0/0x1db0 [ 43.322167] ? sctp_chunk_hold+0x20/0x20 [ 43.326197] ? refcount_sub_and_test+0x115/0x1b0 [ 43.330919] ? refcount_inc+0x50/0x50 [ 43.334684] ? mark_held_locks+0xaf/0x100 [ 43.338810] ? sctp_datamsg_put+0x456/0x560 [ 43.343104] sctp_chunk_put+0x29c/0x420 [ 43.347047] ? sctp_chunk_hold+0x20/0x20 [ 43.351080] ? sctp_transport_dst_confirm+0x50/0x50 [ 43.356068] ? noop_count+0x40/0x40 [ 43.359669] sctp_chunk_free+0x53/0x60 [ 43.363523] __sctp_outq_teardown+0xc7d/0x15a0 [ 43.368077] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 43.372972] ? lock_downgrade+0x990/0x990 [ 43.377089] ? lock_release+0xa40/0xa40 [ 43.381030] ? __free_insn_slot+0x5c0/0x5c0 [ 43.385320] ? update_stack_state+0x700/0x700 [ 43.389785] ? print_usage_bug+0x480/0x480 [ 43.394001] ? is_bpf_text_address+0xa4/0x120 [ 43.398463] ? __kernel_text_address+0xae/0xe0 [ 43.403010] ? unwind_get_return_address+0x61/0xa0 [ 43.407908] ? __save_stack_trace+0x7e/0xd0 [ 43.412203] ? check_noncircular+0x20/0x20 [ 43.416409] ? print_usage_bug+0x480/0x480 [ 43.420609] ? SOFTIRQ_verbose+0x10/0x10 [ 43.424636] ? save_stack_trace+0x16/0x20 [ 43.428748] ? save_trace+0x11f/0x350 [ 43.432521] ? lock_acquire+0x1d5/0x580 [ 43.436463] ? lock_acquire+0x1d5/0x580 [ 43.440404] ? lock_timer_base+0x1a3/0x2b0 [ 43.444611] ? find_held_lock+0x35/0x1d0 [ 43.448647] ? sock_def_wakeup+0x1f9/0x350 [ 43.452856] ? lock_downgrade+0x990/0x990 [ 43.456972] ? lock_release+0xa40/0xa40 [ 43.460926] sctp_outq_free+0x15/0x20 [ 43.464697] sctp_association_free+0x2d0/0x930 [ 43.469250] ? sctp_asconf_queue_teardown+0x700/0x700 [ 43.474409] ? sock_def_wakeup+0x222/0x350 [ 43.478610] ? sk_dst_check+0x560/0x560 [ 43.482554] ? sctp_association_put+0x74/0x2f0 [ 43.487103] ? sctp_association_hold+0x20/0x20 [ 43.491659] ? sctp_sm_lookup_event+0x95/0x3c0 [ 43.496210] sctp_do_sm+0x28e7/0x6d90 [ 43.499977] ? print_usage_bug+0x480/0x480 [ 43.504190] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 43.510220] ? print_usage_bug+0x480/0x480 [ 43.514424] ? print_usage_bug+0x480/0x480 [ 43.518631] ? lock_pin_lock+0x360/0x360 [ 43.522666] ? check_noncircular+0x20/0x20 [ 43.526873] ? check_noncircular+0x20/0x20 [ 43.531077] ? find_held_lock+0x35/0x1d0 [ 43.535118] ? skb_dequeue+0x12a/0x180 [ 43.538971] ? lock_downgrade+0x990/0x990 [ 43.543087] ? do_raw_spin_trylock+0x190/0x190 [ 43.547638] ? mark_held_locks+0xaf/0x100 [ 43.551758] ? trace_hardirqs_on+0xd/0x10 [ 43.555881] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 43.560435] sctp_close+0x3c6/0x980 [ 43.564036] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 43.569287] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 43.574444] ? locks_remove_file+0x414/0x560 [ 43.578820] ? fcntl_setlk+0x10c0/0x10c0 [ 43.582847] ? __fsnotify_parent+0xb4/0x3a0 [ 43.587135] ? ip_mc_drop_socket+0x1ce/0x230 [ 43.591512] inet_release+0xed/0x1c0 [ 43.595198] sock_release+0x8d/0x1e0 [ 43.598877] ? sock_release+0x1e0/0x1e0 [ 43.602816] sock_close+0x16/0x20 [ 43.606237] __fput+0x327/0x7e0 [ 43.609487] ? fput+0x140/0x140 [ 43.612736] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 43.617897] ____fput+0x15/0x20 [ 43.621143] task_work_run+0x18a/0x260 [ 43.625008] ? task_work_cancel+0x210/0x210 [ 43.629304] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 43.634377] ? check_noncircular+0x20/0x20 [ 43.638580] get_signal+0x1440/0x17e0 [ 43.642344] ? trace_hardirqs_on+0xd/0x10 [ 43.646456] ? __local_bh_enable_ip+0x9d/0x160 [ 43.651011] ? bsearch+0x83/0xa0 [ 43.654344] ? cmp_ex_sort+0xb0/0xb0 [ 43.658028] ? search_extable+0x35/0x40 [ 43.661973] ? __get_user_4+0x1b/0x30 [ 43.665739] ? ex_handler_default+0x18/0x90 [ 43.670034] ? fixup_exception+0x93/0xc0 [ 43.674064] ? ptrace_notify+0x130/0x130 [ 43.678095] ? check_noncircular+0x20/0x20 [ 43.682296] ? pgtable_bad+0x110/0x110 [ 43.686156] ? check_noncircular+0x20/0x20 [ 43.690358] ? __bad_area_nosemaphore+0x1f4/0x3e0 [ 43.695176] ? downgrade_write+0x150/0x150 [ 43.699388] do_signal+0x94/0x1ee0 [ 43.702899] ? put_unused_fd+0x62/0x70 [ 43.706755] ? lock_downgrade+0x990/0x990 [ 43.710871] ? setup_sigcontext+0x7d0/0x7d0 [ 43.715161] ? do_raw_spin_trylock+0x190/0x190 [ 43.719710] ? __put_unused_fd+0x183/0x250 [ 43.723911] ? alloc_fdtable+0x280/0x280 [ 43.727939] ? cpumask_weight.constprop.3+0x45/0x45 [ 43.732927] ? _raw_spin_unlock+0x22/0x30 [ 43.737040] ? put_unused_fd+0x62/0x70 [ 43.740891] ? fput+0xd2/0x140 [ 43.744050] ? SYSC_accept4+0x4ec/0x850 [ 43.747992] ? is_prefetch.isra.33+0x420/0x420 [ 43.752543] ? exit_to_usermode_loop+0x98/0x2d0 [ 43.757182] exit_to_usermode_loop+0x21c/0x2d0 [ 43.761733] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 43.767233] ? exit_to_usermode_loop+0x1dc/0x2d0 [ 43.771961] syscall_return_slowpath+0x3a7/0x450 [ 43.776682] ? prepare_exit_to_usermode+0x220/0x220 [ 43.781661] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 43.786557] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.791626] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 43.796353] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 43.801074] RIP: 0033:0x4460d9 [ 43.804231] RSP: 002b:00007fef7ce4ed08 EFLAGS: 00000246 ORIG_RAX: 000000000000002b [ 43.811904] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 00000000004460d9 [ 43.819139] RDX: 0000000020ade000 RSI: 00000000201b4ff0 RDI: 0000000000000003 [ 43.826374] RBP: 0000000000000000 R08: 0000000000000000 R09: 00007fef7ce4f700 [ 43.833608] R10: 00007fef7ce4ed10 R11: 0000000000000246 R12: 0000000000000000 [ 43.840843] R13: 00000000007efe5f R14: 00007fef7ce4f9c0 R15: 0000000000000000 [ 43.848254] Dumping ftrace buffer: [ 43.851829] (ftrace buffer empty) [ 43.855504] Kernel Offset: disabled [ 43.859100] Rebooting in 86400 seconds..