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-1,10.128.0.9' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 55.388330] refcount_t: underflow; use-after-free. [ 55.389175] ------------[ cut here ]------------ [ 55.389837] WARNING: CPU: 0 PID: 2994 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 55.391105] Kernel panic - not syncing: panic_on_warn set ... [ 55.391105] [ 55.392080] CPU: 0 PID: 2994 Comm: syzkaller767675 Not tainted 4.14.0-rc5-mm1+ #20 [ 55.393088] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 55.394426] Call Trace: [ 55.394786] dump_stack+0x194/0x257 [ 55.395281] ? arch_local_irq_restore+0x53/0x53 [ 55.395932] ? vsnprintf+0x1ed/0x1900 [ 55.396452] panic+0x1e4/0x41c [ 55.396888] ? refcount_error_report+0x214/0x214 [ 55.397519] ? show_regs_print_info+0x65/0x65 [ 55.398125] ? __warn+0x1a9/0x1e0 [ 55.398596] ? refcount_sub_and_test+0x167/0x1b0 [ 55.399230] __warn+0x1c4/0x1e0 [ 55.399672] ? refcount_sub_and_test+0x167/0x1b0 [ 55.400307] report_bug+0x211/0x2d0 [ 55.400802] fixup_bug+0x40/0x90 [ 55.401258] do_trap+0x260/0x390 [ 55.401718] do_error_trap+0x120/0x390 [ 55.402239] ? vprintk_emit+0x49b/0x590 [ 55.402774] ? do_trap+0x390/0x390 [ 55.403254] ? refcount_sub_and_test+0x167/0x1b0 [ 55.403887] ? vprintk_emit+0x3ea/0x590 [ 55.404426] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 55.405078] do_invalid_op+0x1b/0x20 [ 55.405577] invalid_op+0x18/0x20 [ 55.406043] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 55.406749] RSP: 0018:ffff8801d299e9c8 EFLAGS: 00010282 [ 55.407460] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 55.408412] RDX: 0000000000000026 RSI: 1ffff1003a533cf9 RDI: ffffed003a533d2d [ 55.409364] RBP: ffff8801d299ea58 R08: 0000000000000001 R09: 0000000000000000 [ 55.416601] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a533d3a [ 55.423834] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d37342bc [ 55.431089] ? refcount_sub_and_test+0x167/0x1b0 [ 55.435815] ? refcount_inc+0x50/0x50 [ 55.439581] ? sctp_outq_free+0x15/0x20 [ 55.443521] ? sctp_do_sm+0x271b/0x6a30 [ 55.447462] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 55.452185] ? sctp_close+0x3c6/0x980 [ 55.455950] ? inet_release+0xed/0x1c0 [ 55.459800] ? sock_release+0x8d/0x1e0 [ 55.463662] sctp_wfree+0x183/0x620 [ 55.467258] ? __sctp_write_space+0x910/0x910 [ 55.471723] skb_release_head_state+0x124/0x200 [ 55.476359] skb_release_all+0x15/0x60 [ 55.480216] consume_skb+0x153/0x490 [ 55.483892] ? sctp_chunk_put+0x99/0x420 [ 55.487916] ? alloc_skb_with_frags+0x750/0x750 [ 55.492550] ? sctp_chunk_hold+0x20/0x20 [ 55.496579] ? refcount_sub_and_test+0x115/0x1b0 [ 55.501298] ? refcount_inc+0x50/0x50 [ 55.505062] ? mark_held_locks+0xaf/0x100 [ 55.509179] ? sctp_datamsg_put+0x456/0x560 [ 55.513471] sctp_chunk_put+0x29c/0x420 [ 55.517412] ? sctp_chunk_hold+0x20/0x20 [ 55.521441] ? sctp_transport_dst_confirm+0x50/0x50 [ 55.526425] ? sctp_sched_fcfs_dequeue+0x198/0x290 [ 55.531321] ? sctp_sched_dequeue_common+0x5d0/0x5d0 [ 55.536396] sctp_chunk_free+0x53/0x60 [ 55.540251] __sctp_outq_teardown+0xa5b/0x1230 [ 55.544806] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 55.549701] ? __kernel_text_address+0xd/0x40 [ 55.554164] ? unwind_get_return_address+0x61/0xa0 [ 55.559078] ? __save_stack_trace+0x7e/0xd0 [ 55.563373] ? add_lock_to_list.isra.32+0x292/0x39b [ 55.568362] ? check_noncircular+0x20/0x20 [ 55.572564] ? print_irqtrace_events+0x270/0x270 [ 55.577293] ? lock_acquire+0x1d5/0x580 [ 55.581231] ? lock_acquire+0x1d5/0x580 [ 55.585171] ? lock_timer_base+0x1a3/0x2b0 [ 55.589375] ? find_held_lock+0x35/0x1d0 [ 55.593409] ? sock_def_wakeup+0x1f9/0x350 [ 55.597609] ? lock_downgrade+0x990/0x990 [ 55.601728] ? lock_release+0xa40/0xa40 [ 55.605677] sctp_outq_free+0x15/0x20 [ 55.609444] sctp_association_free+0x2d0/0x930 [ 55.613997] ? sctp_asconf_queue_teardown+0x700/0x700 [ 55.619151] ? sock_def_wakeup+0x222/0x350 [ 55.623351] ? sk_dst_check+0x560/0x560 [ 55.627291] ? sctp_association_put+0x74/0x2f0 [ 55.631839] ? sctp_association_hold+0x20/0x20 [ 55.636385] ? __lock_is_held+0xb6/0x140 [ 55.640420] sctp_do_sm+0x271b/0x6a30 [ 55.644197] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 55.650225] ? print_irqtrace_events+0x270/0x270 [ 55.654945] ? __lock_acquire+0x6aa/0x3d50 [ 55.659148] ? print_irqtrace_events+0x270/0x270 [ 55.663884] ? find_held_lock+0x35/0x1d0 [ 55.667917] ? skb_dequeue+0x12a/0x180 [ 55.671771] ? lock_downgrade+0x990/0x990 [ 55.675888] ? do_raw_spin_trylock+0x190/0x190 [ 55.680448] ? mark_held_locks+0xaf/0x100 [ 55.684568] ? trace_hardirqs_on+0xd/0x10 [ 55.688688] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 55.693241] sctp_close+0x3c6/0x980 [ 55.696840] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 55.702077] ? __lock_acquire+0x6aa/0x3d50 [ 55.706277] ? check_noncircular+0x20/0x20 [ 55.710479] ? __lock_acquire+0x6aa/0x3d50 [ 55.714679] ? check_noncircular+0x20/0x20 [ 55.718880] ? locks_remove_file+0x3fa/0x5a0 [ 55.723261] ? fcntl_setlk+0x10c0/0x10c0 [ 55.727290] ? __fsnotify_parent+0xb4/0x3a0 [ 55.731576] ? ip_mc_drop_socket+0x1ce/0x230 [ 55.735954] inet_release+0xed/0x1c0 [ 55.739635] sock_release+0x8d/0x1e0 [ 55.743313] ? sock_release+0x1e0/0x1e0 [ 55.747252] sock_close+0x16/0x20 [ 55.750672] __fput+0x327/0x7e0 [ 55.753925] ? fput+0x140/0x140 [ 55.757172] ? _raw_spin_unlock_irq+0x27/0x70 [ 55.761638] ____fput+0x15/0x20 [ 55.764884] task_work_run+0x199/0x270 [ 55.768739] ? task_work_cancel+0x210/0x210 [ 55.773026] ? __do_page_fault+0x3d6/0xd60 [ 55.777234] get_signal+0x1343/0x16d0 [ 55.781003] ? mm_fault_error+0x2c0/0x2c0 [ 55.785122] ? ptrace_notify+0x130/0x130 [ 55.789147] ? check_noncircular+0x20/0x20 [ 55.793349] ? __do_page_fault+0xd60/0xd60 [ 55.797547] ? do_page_fault+0xee/0x720 [ 55.801486] ? __do_page_fault+0xd60/0xd60 [ 55.805686] ? check_noncircular+0x20/0x20 [ 55.809888] ? find_held_lock+0x35/0x1d0 [ 55.813915] ? retint_kernel+0x10/0x10 [ 55.817776] do_signal+0x94/0x1ee0 [ 55.821287] ? put_unused_fd+0x62/0x70 [ 55.825139] ? lock_downgrade+0x990/0x990 [ 55.829254] ? setup_sigcontext+0x7d0/0x7d0 [ 55.833540] ? do_raw_spin_trylock+0x190/0x190 [ 55.838090] ? __put_unused_fd+0x183/0x250 [ 55.842293] ? alloc_fdtable+0x280/0x280 [ 55.846325] ? cpumask_weight.constprop.1+0x48/0x48 [ 55.851309] ? _copy_to_user+0xa2/0xc0 [ 55.855168] ? _raw_spin_unlock+0x22/0x30 [ 55.859287] ? fput+0xd2/0x140 [ 55.862444] ? SYSC_accept4+0x4ec/0x850 [ 55.866386] ? exit_to_usermode_loop+0x8c/0x310 [ 55.871027] exit_to_usermode_loop+0x214/0x310 [ 55.875578] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 55.881078] ? _raw_spin_unlock_irq+0x27/0x70 [ 55.885539] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 55.890527] syscall_return_slowpath+0x42f/0x510 [ 55.895246] ? finish_task_switch+0x1aa/0x740 [ 55.899708] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 55.904690] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 55.909585] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 55.914567] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 55.919293] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 55.924014] RIP: 0033:0x446539 [ 55.927171] RSP: 002b:00007f99820c0dc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000120 [ 55.934844] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000446539 [ 55.942079] RDX: 0000000020137ffc RSI: 0000000020b53ff0 RDI: 0000000000000003 [ 55.949314] RBP: 0000000000000000 R08: 00007f99820c1700 R09: 00007f99820c1700 [ 55.956549] R10: 0000000000080000 R11: 0000000000000202 R12: 0000000000000000 [ 55.963782] R13: 00000000007efe7f R14: 00007f99820c19c0 R15: 0000000000000000 [ 55.971188] Dumping ftrace buffer: [ 55.974735] (ftrace buffer empty) [ 55.978409] Kernel Offset: disabled [ 55.982003] Rebooting in 86400 seconds..