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-next-kasan-gce-7,10.128.0.45' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 53.383398] refcount_t: underflow; use-after-free. [ 53.384316] ------------[ cut here ]------------ [ 53.385007] WARNING: CPU: 1 PID: 2997 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 53.386408] Kernel panic - not syncing: panic_on_warn set ... [ 53.386408] [ 53.387383] CPU: 1 PID: 2997 Comm: syzkaller899608 Not tainted 4.14.0-rc5-next-20171018+ #36 [ 53.388557] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 53.389827] Call Trace: [ 53.390197] dump_stack+0x194/0x257 [ 53.390702] ? arch_local_irq_restore+0x53/0x53 [ 53.391333] ? vsnprintf+0x1ed/0x1900 [ 53.391854] panic+0x1e4/0x41c [ 53.392291] ? refcount_error_report+0x214/0x214 [ 53.392946] ? show_regs_print_info+0x65/0x65 [ 53.393592] ? __warn+0x1a9/0x1e0 [ 53.394080] ? refcount_sub_and_test+0x167/0x1b0 [ 53.394741] __warn+0x1c4/0x1e0 [ 53.395234] ? refcount_sub_and_test+0x167/0x1b0 [ 53.395893] report_bug+0x211/0x2d0 [ 53.396432] fixup_bug+0x40/0x90 [ 53.396923] do_trap+0x260/0x390 [ 53.397414] do_error_trap+0x120/0x390 [ 53.397993] ? vprintk_emit+0x49b/0x590 [ 53.398563] ? do_trap+0x390/0x390 [ 53.399056] ? refcount_sub_and_test+0x167/0x1b0 [ 53.399724] ? vprintk_emit+0x3ea/0x590 [ 53.400281] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 53.400969] do_invalid_op+0x1b/0x20 [ 53.401516] invalid_op+0x18/0x20 [ 53.401997] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 53.402737] RSP: 0018:ffff8801d208e9c8 EFLAGS: 00010282 [ 53.403557] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 53.410884] RDX: 0000000000000026 RSI: 1ffff1003a411cf9 RDI: ffffed003a411d2d [ 53.418154] RBP: ffff8801d208ea58 R08: 0000000000000001 R09: 0000000000000000 [ 53.425430] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a411d3a [ 53.432714] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d1c2e2bc [ 53.440032] ? refcount_sub_and_test+0x167/0x1b0 [ 53.444797] ? refcount_inc+0x50/0x50 [ 53.448575] ? sctp_outq_free+0x15/0x20 [ 53.452522] ? sctp_do_sm+0x271b/0x6a30 [ 53.456470] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 53.461197] ? sctp_close+0x3c6/0x980 [ 53.464969] ? inet_release+0xed/0x1c0 [ 53.468828] ? sock_release+0x8d/0x1e0 [ 53.472691] sctp_wfree+0x183/0x620 [ 53.476306] ? __sctp_write_space+0x910/0x910 [ 53.480776] skb_release_head_state+0x124/0x200 [ 53.485441] skb_release_all+0x15/0x60 [ 53.489318] consume_skb+0x153/0x490 [ 53.493003] ? sctp_chunk_put+0x99/0x420 [ 53.497034] ? alloc_skb_with_frags+0x750/0x750 [ 53.501675] ? sctp_chunk_hold+0x20/0x20 [ 53.505714] ? refcount_sub_and_test+0x115/0x1b0 [ 53.510442] ? refcount_inc+0x50/0x50 [ 53.514213] ? mark_held_locks+0xaf/0x100 [ 53.518334] ? sctp_datamsg_put+0x456/0x560 [ 53.522634] sctp_chunk_put+0x29c/0x420 [ 53.526586] ? sctp_chunk_hold+0x20/0x20 [ 53.530707] ? sctp_transport_dst_confirm+0x50/0x50 [ 53.535703] ? sctp_sched_fcfs_dequeue+0x198/0x290 [ 53.540604] ? sctp_sched_dequeue_common+0x5d0/0x5d0 [ 53.545687] sctp_chunk_free+0x53/0x60 [ 53.549546] __sctp_outq_teardown+0xa5b/0x1230 [ 53.554105] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 53.559014] ? __kernel_text_address+0xd/0x40 [ 53.563487] ? unwind_get_return_address+0x61/0xa0 [ 53.568390] ? __save_stack_trace+0x7e/0xd0 [ 53.572687] ? add_lock_to_list.isra.32+0x292/0x39b [ 53.577682] ? check_noncircular+0x20/0x20 [ 53.581891] ? print_irqtrace_events+0x270/0x270 [ 53.586624] ? lock_acquire+0x1d5/0x580 [ 53.590579] ? lock_acquire+0x1d5/0x580 [ 53.594529] ? lock_timer_base+0x1a3/0x2b0 [ 53.598738] ? find_held_lock+0x35/0x1d0 [ 53.602778] ? sock_def_wakeup+0x1f9/0x350 [ 53.606995] ? lock_downgrade+0x990/0x990 [ 53.611117] ? lock_release+0xa40/0xa40 [ 53.615068] sctp_outq_free+0x15/0x20 [ 53.618863] sctp_association_free+0x2d0/0x930 [ 53.623451] ? sctp_asconf_queue_teardown+0x700/0x700 [ 53.628647] ? sock_def_wakeup+0x222/0x350 [ 53.632887] ? sk_dst_check+0x560/0x560 [ 53.636861] ? sctp_association_put+0x74/0x2f0 [ 53.641446] ? sctp_association_hold+0x20/0x20 [ 53.646034] ? __lock_is_held+0xb6/0x140 [ 53.650105] sctp_do_sm+0x271b/0x6a30 [ 53.653924] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 53.659994] ? print_irqtrace_events+0x270/0x270 [ 53.664745] ? __lock_acquire+0x6aa/0x3d50 [ 53.668957] ? print_irqtrace_events+0x270/0x270 [ 53.673700] ? find_held_lock+0x35/0x1d0 [ 53.677742] ? skb_dequeue+0x12a/0x180 [ 53.681599] ? lock_downgrade+0x990/0x990 [ 53.685823] ? do_raw_spin_trylock+0x190/0x190 [ 53.690399] ? mark_held_locks+0xaf/0x100 [ 53.694525] ? trace_hardirqs_on+0xd/0x10 [ 53.698663] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 53.703227] sctp_close+0x3c6/0x980 [ 53.706839] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 53.712093] ? __lock_acquire+0x6aa/0x3d50 [ 53.716301] ? check_noncircular+0x20/0x20 [ 53.720510] ? __lock_acquire+0x6aa/0x3d50 [ 53.724715] ? check_noncircular+0x20/0x20 [ 53.728930] ? locks_remove_file+0x3fa/0x5a0 [ 53.733315] ? fcntl_setlk+0x10c0/0x10c0 [ 53.737358] ? __fsnotify_parent+0xb4/0x3a0 [ 53.741656] ? ip_mc_drop_socket+0x1ce/0x230 [ 53.746043] inet_release+0xed/0x1c0 [ 53.749738] sock_release+0x8d/0x1e0 [ 53.753426] ? sock_release+0x1e0/0x1e0 [ 53.757370] sock_close+0x16/0x20 [ 53.760798] __fput+0x327/0x7e0 [ 53.764068] ? fput+0x140/0x140 [ 53.767322] ? _raw_spin_unlock_irq+0x27/0x70 [ 53.771807] ____fput+0x15/0x20 [ 53.775061] task_work_run+0x199/0x270 [ 53.778922] ? task_work_cancel+0x210/0x210 [ 53.783229] ? __do_page_fault+0x3d6/0xd60 [ 53.787441] get_signal+0x1343/0x16d0 [ 53.791229] ? mm_fault_error+0x2c0/0x2c0 [ 53.795350] ? ptrace_notify+0x130/0x130 [ 53.799386] ? check_noncircular+0x20/0x20 [ 53.803593] ? __do_page_fault+0xd60/0xd60 [ 53.807796] ? do_page_fault+0xee/0x720 [ 53.811743] ? __do_page_fault+0xd60/0xd60 [ 53.815950] ? check_noncircular+0x20/0x20 [ 53.820156] ? find_held_lock+0x35/0x1d0 [ 53.824191] ? retint_kernel+0x10/0x10 [ 53.828060] do_signal+0x94/0x1ee0 [ 53.831576] ? put_unused_fd+0x62/0x70 [ 53.835432] ? lock_downgrade+0x990/0x990 [ 53.839552] ? setup_sigcontext+0x7d0/0x7d0 [ 53.843846] ? do_raw_spin_trylock+0x190/0x190 [ 53.848401] ? __put_unused_fd+0x183/0x250 [ 53.852606] ? alloc_fdtable+0x280/0x280 [ 53.856636] ? cpumask_weight.constprop.1+0x48/0x48 [ 53.861646] ? _copy_to_user+0xa2/0xc0 [ 53.865525] ? _raw_spin_unlock+0x22/0x30 [ 53.869645] ? fput+0xd2/0x140 [ 53.872807] ? SYSC_accept4+0x4ec/0x850 [ 53.876757] ? exit_to_usermode_loop+0x8c/0x310 [ 53.881403] exit_to_usermode_loop+0x214/0x310 [ 53.885957] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 53.891466] ? _raw_spin_unlock_irq+0x27/0x70 [ 53.895931] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 53.900922] syscall_return_slowpath+0x42f/0x510 [ 53.905652] ? finish_task_switch+0x1aa/0x740 [ 53.910120] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 53.915108] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 53.920007] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 53.924994] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 53.929727] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 53.934454] RIP: 0033:0x446889 [ 53.937615] RSP: 002b:00007f4878db6d08 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 [ 53.945293] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000446889 [ 53.952531] RDX: 0000000020137ffc RSI: 0000000020b53ff0 RDI: 0000000000000003 [ 53.959788] RBP: 0000000000000000 R08: 00007f4878db7700 R09: 00007f4878db7700 [ 53.967029] R10: 0000000000080000 R11: 0000000000000246 R12: 0000000000000000 [ 53.974269] R13: 00000000007efe7f R14: 00007f4878db79c0 R15: 0000000000000000 [ 53.981720] Dumping ftrace buffer: [ 53.985322] (ftrace buffer empty) [ 53.989016] Kernel Offset: disabled [ 53.992619] Rebooting in 86400 seconds..