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-386-0,10.128.15.229' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 62.775356] refcount_t: underflow; use-after-free. [ 62.776250] ------------[ cut here ]------------ [ 62.776909] WARNING: CPU: 0 PID: 2990 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 62.778171] Kernel panic - not syncing: panic_on_warn set ... [ 62.778171] [ 62.779146] CPU: 0 PID: 2990 Comm: syzkaller520154 Not tainted 4.14.0-rc6+ #56 [ 62.780127] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 62.781344] Call Trace: [ 62.781701] dump_stack+0x194/0x257 [ 62.782192] ? arch_local_irq_restore+0x53/0x53 [ 62.782824] panic+0x1e4/0x417 [ 62.783292] ? __warn+0x1d9/0x1d9 [ 62.783757] ? show_regs_print_info+0x65/0x65 [ 62.784394] ? refcount_sub_and_test+0x167/0x1b0 [ 62.785142] __warn+0x1c4/0x1d9 [ 62.785605] ? refcount_sub_and_test+0x167/0x1b0 [ 62.786262] report_bug+0x211/0x2d0 [ 62.786757] fixup_bug+0x40/0x90 [ 62.787212] do_trap+0x260/0x390 [ 62.787674] do_error_trap+0x120/0x390 [ 62.788204] ? vprintk_emit+0x49b/0x590 [ 62.788756] ? do_trap+0x390/0x390 [ 62.789233] ? refcount_sub_and_test+0x167/0x1b0 [ 62.789882] ? vprintk_emit+0x3ea/0x590 [ 62.790422] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 62.791072] do_invalid_op+0x1b/0x20 [ 62.791573] invalid_op+0x18/0x20 [ 62.792053] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 62.792760] RSP: 0018:ffff8801d1ff6858 EFLAGS: 00010286 [ 62.793471] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 62.794472] RDX: 0000000000000026 RSI: 1ffff1003a3feccb RDI: ffffed003a3fecff [ 62.795457] RBP: ffff8801d1ff68e8 R08: 0000000000000001 R09: 0000000000000000 [ 62.796410] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a3fed0c [ 62.803646] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d1fd52bc [ 62.810899] ? refcount_sub_and_test+0x167/0x1b0 [ 62.815624] ? refcount_inc+0x50/0x50 [ 62.819391] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 62.824124] ? sctp_association_free+0x2d0/0x930 [ 62.828849] ? sctp_do_sm+0x28e7/0x6dd0 [ 62.832788] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 62.837508] ? sctp_close+0x3c6/0x980 [ 62.841273] ? inet_release+0xed/0x1c0 [ 62.845132] sctp_wfree+0x183/0x620 [ 62.848725] ? __sctp_write_space+0x910/0x910 [ 62.853190] skb_release_head_state+0x124/0x200 [ 62.857828] skb_release_all+0x15/0x60 [ 62.861685] consume_skb+0x153/0x490 [ 62.865367] ? sctp_chunk_put+0x99/0x420 [ 62.869394] ? alloc_skb_with_frags+0x710/0x710 [ 62.874030] ? sctp_chunk_hold+0x20/0x20 [ 62.878059] ? refcount_sub_and_test+0x115/0x1b0 [ 62.882782] ? refcount_inc+0x50/0x50 [ 62.886549] ? mark_held_locks+0xaf/0x100 [ 62.890664] ? sctp_datamsg_put+0x456/0x560 [ 62.894958] sctp_chunk_put+0x29c/0x420 [ 62.898902] ? sctp_chunk_hold+0x20/0x20 [ 62.902933] ? sctp_transport_dst_confirm+0x50/0x50 [ 62.907915] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 62.913071] ? lock_release+0xa40/0xa40 [ 62.917017] ? show_initstate+0xb0/0xb0 [ 62.920962] sctp_chunk_free+0x53/0x60 [ 62.924817] __sctp_outq_teardown+0xc7d/0x15a0 [ 62.929372] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 62.934272] ? rcutorture_record_progress+0x10/0x10 [ 62.939265] ? is_bpf_text_address+0xa4/0x120 [ 62.943736] ? kernel_text_address+0x102/0x140 [ 62.948285] ? __kernel_text_address+0xd/0x40 [ 62.952746] ? unwind_get_return_address+0x61/0xa0 [ 62.957644] ? __save_stack_trace+0x7e/0xd0 [ 62.961938] ? add_lock_to_list.isra.33+0x292/0x39b [ 62.966927] ? check_noncircular+0x20/0x20 [ 62.971130] ? print_irqtrace_events+0x270/0x270 [ 62.975850] ? check_noncircular+0x20/0x20 [ 62.980060] ? lock_acquire+0x1d5/0x580 [ 62.983999] ? lock_acquire+0x1d5/0x580 [ 62.987939] ? lock_timer_base+0x1a3/0x2b0 [ 62.992142] ? find_held_lock+0x35/0x1d0 [ 62.996175] ? sock_def_wakeup+0x1f9/0x350 [ 63.000376] ? lock_downgrade+0x990/0x990 [ 63.004495] ? lock_release+0xa40/0xa40 [ 63.008468] sctp_outq_free+0x15/0x20 [ 63.012237] sctp_association_free+0x2d0/0x930 [ 63.016790] ? sctp_asconf_queue_teardown+0x700/0x700 [ 63.021949] ? sock_def_wakeup+0x222/0x350 [ 63.026150] ? sk_dst_check+0x560/0x560 [ 63.030093] ? sctp_association_put+0x74/0x2f0 [ 63.034641] ? sctp_association_hold+0x20/0x20 [ 63.039188] ? lock_downgrade+0x990/0x990 [ 63.043313] sctp_do_sm+0x28e7/0x6dd0 [ 63.047095] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 63.053119] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 63.058277] ? print_irqtrace_events+0x270/0x270 [ 63.062998] ? __lock_acquire+0x6aa/0x3d50 [ 63.067205] ? print_irqtrace_events+0x270/0x270 [ 63.071930] ? check_usage_backwards+0x20a/0x420 [ 63.076664] ? find_held_lock+0x35/0x1d0 [ 63.080698] ? skb_dequeue+0x12a/0x180 [ 63.084552] ? lock_downgrade+0x990/0x990 [ 63.088670] ? do_raw_spin_trylock+0x190/0x190 [ 63.093223] ? mark_held_locks+0xaf/0x100 [ 63.097347] ? trace_hardirqs_on+0xd/0x10 [ 63.101467] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 63.106022] sctp_close+0x3c6/0x980 [ 63.109613] ? check_noncircular+0x20/0x20 [ 63.113821] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 63.119065] ? check_noncircular+0x20/0x20 [ 63.123266] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 63.128425] ? search_extable+0x35/0x40 [ 63.132365] ? copy_user_handle_tail+0x40/0x80 [ 63.136912] ? ex_handler_default+0x18/0x90 [ 63.141197] ? __pte+0x60/0x60 [ 63.144361] ? locks_remove_file+0x3fa/0x5a0 [ 63.148738] ? fcntl_setlk+0x10c0/0x10c0 [ 63.152767] ? __fsnotify_parent+0xb4/0x3a0 [ 63.157063] ? ip_mc_drop_socket+0x1ce/0x230 [ 63.161443] inet_release+0xed/0x1c0 [ 63.165124] sock_release+0x8d/0x1e0 [ 63.168806] ? sock_release+0x1e0/0x1e0 [ 63.172745] sock_close+0x16/0x20 [ 63.176165] __fput+0x327/0x7e0 [ 63.179420] ? fput+0x140/0x140 [ 63.182667] ? _raw_spin_unlock_irq+0x27/0x70 [ 63.187134] ____fput+0x15/0x20 [ 63.190378] task_work_run+0x199/0x270 [ 63.194234] ? task_work_cancel+0x210/0x210 [ 63.198532] ? check_noncircular+0x20/0x20 [ 63.202734] ? __do_page_fault+0xd60/0xd60 [ 63.206932] ? do_page_fault+0xee/0x720 [ 63.210876] get_signal+0x1343/0x16d0 [ 63.214643] ? check_noncircular+0x20/0x20 [ 63.218844] ? find_held_lock+0x35/0x1d0 [ 63.222873] ? ptrace_notify+0x130/0x130 [ 63.226902] ? find_held_lock+0x35/0x1d0 [ 63.230935] ? put_unused_fd+0x62/0x70 [ 63.234790] ? lock_downgrade+0x990/0x990 [ 63.238905] ? do_raw_spin_trylock+0x190/0x190 [ 63.243460] do_signal+0x94/0x1ee0 [ 63.246965] ? alloc_fdtable+0x280/0x280 [ 63.250991] ? cpumask_weight.constprop.3+0x45/0x45 [ 63.255975] ? _copy_to_user+0xa2/0xc0 [ 63.259834] ? setup_sigcontext+0x7d0/0x7d0 [ 63.264119] ? fput+0xd2/0x140 [ 63.267278] ? SYSC_accept4+0x4ec/0x850 [ 63.271224] ? kernel_accept+0x2f0/0x2f0 [ 63.275269] ? handle_mm_fault+0x410/0x8d0 [ 63.279469] ? down_read_trylock+0xdb/0x170 [ 63.283756] ? __do_page_fault+0x31e/0xd60 [ 63.287957] ? __handle_mm_fault+0x39c0/0x39c0 [ 63.292505] ? vmacache_find+0x5f/0x280 [ 63.296446] ? vmacache_update+0xfe/0x130 [ 63.300564] ? exit_to_usermode_loop+0x8c/0x310 [ 63.305206] exit_to_usermode_loop+0x214/0x310 [ 63.309758] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 63.315272] do_fast_syscall_32+0x83e/0xf05 [ 63.319566] ? do_int80_syscall_32+0x940/0x940 [ 63.324120] ? syscall_return_slowpath+0x2b3/0x510 [ 63.329015] ? finish_task_switch+0x1aa/0x740 [ 63.333480] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 63.338464] ? retint_user+0x18/0x20 [ 63.342149] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 63.346964] entry_SYSENTER_compat+0x51/0x60 [ 63.351336] RIP: 0023:0xf7fdcc79 [ 63.354665] RSP: 002b:00000000f67d51ec EFLAGS: 00000296 ORIG_RAX: 000000000000016c [ 63.362347] RAX: fffffffffffffff2 RBX: 0000000000000003 RCX: 0000000020b53ff0 [ 63.369584] RDX: 0000000020137ffc RSI: 0000000000080000 RDI: 0000000000000000 [ 63.376819] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 63.384062] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 63.391802] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 63.399220] Dumping ftrace buffer: [ 63.402765] (ftrace buffer empty) [ 63.406444] Kernel Offset: disabled [ 63.410041] Rebooting in 86400 seconds..