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-3,10.128.0.16' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 42.938319] refcount_t: underflow; use-after-free. [ 42.939203] ------------[ cut here ]------------ [ 42.939856] WARNING: CPU: 1 PID: 3006 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 42.941166] Kernel panic - not syncing: panic_on_warn set ... [ 42.941166] [ 42.942138] CPU: 1 PID: 3006 Comm: syzkaller307348 Not tainted 4.13.0-rc5+ #42 [ 42.943135] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.944390] Call Trace: [ 42.944753] dump_stack+0x194/0x257 [ 42.945246] ? arch_local_irq_restore+0x53/0x53 [ 42.945880] panic+0x1e4/0x417 [ 42.946315] ? __warn+0x1d9/0x1d9 [ 42.946793] ? show_regs_print_info+0x65/0x65 [ 42.947451] ? refcount_sub_and_test+0x167/0x1b0 [ 42.948084] __warn+0x1c4/0x1d9 [ 42.948527] ? refcount_sub_and_test+0x167/0x1b0 [ 42.949163] report_bug+0x211/0x2d0 [ 42.949665] fixup_bug+0x40/0x90 [ 42.950140] do_trap+0x260/0x390 [ 42.950603] do_error_trap+0x120/0x390 [ 42.951130] ? do_trap+0x390/0x390 [ 42.951619] ? refcount_sub_and_test+0x167/0x1b0 [ 42.952251] ? vprintk_emit+0x3ea/0x590 [ 42.952794] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.953475] do_invalid_op+0x1b/0x20 [ 42.953974] invalid_op+0x1e/0x30 [ 42.954439] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 42.955148] RSP: 0018:ffff8801d003e310 EFLAGS: 00010282 [ 42.955859] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 42.956810] RDX: 0000000000000026 RSI: 1ffff1003a007c22 RDI: ffffed003a007c56 [ 42.957780] RBP: ffff8801d003e3a0 R08: 0000000000000001 R09: 0000000000000000 [ 42.960588] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a007c63 [ 42.967826] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d2272a3c [ 42.975091] ? refcount_inc+0x50/0x50 [ 42.978862] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 42.983588] ? sctp_association_free+0x2d0/0x930 [ 42.988310] ? sctp_do_sm+0x28e7/0x6d90 [ 42.992260] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.996982] ? sctp_close+0x3c6/0x980 [ 43.000753] ? inet_release+0xed/0x1c0 [ 43.004611] sctp_wfree+0x183/0x620 [ 43.008206] ? __sctp_write_space+0x910/0x910 [ 43.012673] skb_release_head_state+0x124/0x200 [ 43.017308] skb_release_all+0x15/0x60 [ 43.021160] consume_skb+0x153/0x490 [ 43.024842] ? sctp_chunk_put+0x99/0x420 [ 43.028869] ? pskb_carve+0x1db0/0x1db0 [ 43.032810] ? sctp_chunk_hold+0x20/0x20 [ 43.036843] ? refcount_sub_and_test+0x115/0x1b0 [ 43.041567] ? refcount_inc+0x50/0x50 [ 43.045334] ? mark_held_locks+0xaf/0x100 [ 43.049450] ? sctp_datamsg_put+0x456/0x560 [ 43.053745] sctp_chunk_put+0x29c/0x420 [ 43.057688] ? sctp_chunk_hold+0x20/0x20 [ 43.061722] ? sctp_transport_dst_confirm+0x50/0x50 [ 43.066713] ? noop_count+0x40/0x40 [ 43.070317] sctp_chunk_free+0x53/0x60 [ 43.074174] __sctp_outq_teardown+0xc7d/0x15a0 [ 43.078732] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 43.083637] ? lock_downgrade+0x990/0x990 [ 43.087753] ? lock_release+0xa40/0xa40 [ 43.091697] ? __free_insn_slot+0x5c0/0x5c0 [ 43.095988] ? update_stack_state+0x700/0x700 [ 43.100449] ? print_usage_bug+0x480/0x480 [ 43.104661] ? is_bpf_text_address+0xa4/0x120 [ 43.109127] ? __kernel_text_address+0xae/0xe0 [ 43.113676] ? unwind_get_return_address+0x61/0xa0 [ 43.118575] ? __save_stack_trace+0x7e/0xd0 [ 43.122871] ? check_noncircular+0x20/0x20 [ 43.127075] ? print_usage_bug+0x480/0x480 [ 43.131277] ? SOFTIRQ_verbose+0x10/0x10 [ 43.135312] ? save_stack_trace+0x16/0x20 [ 43.139427] ? save_trace+0x11f/0x350 [ 43.143199] ? lock_acquire+0x1d5/0x580 [ 43.147141] ? lock_acquire+0x1d5/0x580 [ 43.151082] ? lock_timer_base+0x1a3/0x2b0 [ 43.155285] ? find_held_lock+0x35/0x1d0 [ 43.159321] ? sock_def_wakeup+0x1f9/0x350 [ 43.163522] ? lock_downgrade+0x990/0x990 [ 43.167642] ? lock_release+0xa40/0xa40 [ 43.171592] sctp_outq_free+0x15/0x20 [ 43.175362] sctp_association_free+0x2d0/0x930 [ 43.179915] ? sctp_asconf_queue_teardown+0x700/0x700 [ 43.185073] ? sock_def_wakeup+0x222/0x350 [ 43.189274] ? sk_dst_check+0x560/0x560 [ 43.193218] ? sctp_association_put+0x74/0x2f0 [ 43.197767] ? sctp_association_hold+0x20/0x20 [ 43.202313] ? print_usage_bug+0x480/0x480 [ 43.206520] ? sctp_sm_lookup_event+0x95/0x3c0 [ 43.211073] sctp_do_sm+0x28e7/0x6d90 [ 43.214840] ? check_noncircular+0x20/0x20 [ 43.219053] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 43.225081] ? print_usage_bug+0x480/0x480 [ 43.229284] ? exit_to_usermode_loop+0x224/0x300 [ 43.234004] ? syscall_return_slowpath+0x3a7/0x450 [ 43.238903] ? print_usage_bug+0x480/0x480 [ 43.243102] ? find_held_lock+0x35/0x1d0 [ 43.247142] ? find_held_lock+0x35/0x1d0 [ 43.251218] ? skb_dequeue+0x12a/0x180 [ 43.255073] ? lock_downgrade+0x990/0x990 [ 43.259192] ? do_raw_spin_trylock+0x190/0x190 [ 43.263751] ? mark_held_locks+0xaf/0x100 [ 43.267872] ? trace_hardirqs_on+0xd/0x10 [ 43.271995] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 43.276548] sctp_close+0x3c6/0x980 [ 43.280148] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 43.285393] ? unwind_get_return_address+0x61/0xa0 [ 43.290292] ? trace_hardirqs_off+0xd/0x10 [ 43.294495] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 43.299575] ? check_noncircular+0x20/0x20 [ 43.303782] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 43.308245] ? ipv6_sock_mc_close+0x148/0x1a0 [ 43.312708] ? ipv6_sock_ac_drop+0x580/0x580 [ 43.317082] ? ip_mc_drop_socket+0x1ce/0x230 [ 43.321458] ? __fsnotify_parent+0xb4/0x3a0 [ 43.325751] inet_release+0xed/0x1c0 [ 43.329434] inet6_release+0x50/0x70 [ 43.333116] sock_release+0x8d/0x1e0 [ 43.336796] ? sock_release+0x1e0/0x1e0 [ 43.340735] sock_close+0x16/0x20 [ 43.344156] __fput+0x327/0x7e0 [ 43.347406] ? fput+0x140/0x140 [ 43.350655] ? do_raw_spin_trylock+0x190/0x190 [ 43.355208] ? check_same_owner+0x320/0x320 [ 43.359500] ____fput+0x15/0x20 [ 43.362750] task_work_run+0x18a/0x260 [ 43.366607] ? task_work_cancel+0x210/0x210 [ 43.370906] ? _raw_spin_unlock+0x22/0x30 [ 43.375021] ? switch_task_namespaces+0x87/0xc0 [ 43.379661] do_exit+0xa3a/0x1b10 [ 43.383082] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 43.388247] ? print_usage_bug+0x480/0x480 [ 43.392455] ? mm_update_next_owner+0x930/0x930 [ 43.397089] ? check_noncircular+0x20/0x20 [ 43.401294] ? check_noncircular+0x20/0x20 [ 43.405501] ? find_held_lock+0x35/0x1d0 [ 43.409534] ? find_held_lock+0x35/0x1d0 [ 43.413569] ? check_noncircular+0x20/0x20 [ 43.417772] ? check_noncircular+0x20/0x20 [ 43.421974] ? lock_downgrade+0x990/0x990 [ 43.426094] ? do_raw_spin_trylock+0x190/0x190 [ 43.430647] ? reacquire_held_locks+0x1fd/0x3d0 [ 43.435279] ? mark_held_locks+0xaf/0x100 [ 43.439391] ? reacquire_held_locks+0x1fd/0x3d0 [ 43.444027] ? check_noncircular+0x20/0x20 [ 43.448233] ? find_held_lock+0x35/0x1d0 [ 43.452269] ? release_sock+0x1d4/0x2a0 [ 43.456213] ? lock_downgrade+0x990/0x990 [ 43.460325] ? lock_downgrade+0x990/0x990 [ 43.464443] ? find_held_lock+0x35/0x1d0 [ 43.468477] ? get_signal+0x855/0x17e0 [ 43.472331] ? lock_downgrade+0x990/0x990 [ 43.476452] do_group_exit+0x149/0x400 [ 43.480306] ? __lock_is_held+0xb6/0x140 [ 43.484333] ? SyS_exit+0x30/0x30 [ 43.487755] ? _raw_spin_unlock_irq+0x27/0x70 [ 43.492218] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.497209] get_signal+0x7e8/0x17e0 [ 43.500916] ? ptrace_notify+0x130/0x130 [ 43.504946] ? inet_autobind+0x1f/0x180 [ 43.508887] ? __local_bh_enable_ip+0x9d/0x160 [ 43.513436] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.518419] ? release_sock+0x1d4/0x2a0 [ 43.522360] ? trace_hardirqs_on+0xd/0x10 [ 43.526473] ? __local_bh_enable_ip+0x9d/0x160 [ 43.531026] ? _raw_spin_unlock_bh+0x30/0x40 [ 43.535403] ? release_sock+0x1d4/0x2a0 [ 43.539347] ? trace_hardirqs_on+0xd/0x10 [ 43.543471] do_signal+0x94/0x1ee0 [ 43.546980] ? inet_sendmsg+0x11f/0x5e0 [ 43.550921] ? inet_sendmsg+0x126/0x5e0 [ 43.554864] ? __might_sleep+0x95/0x190 [ 43.558808] ? setup_sigcontext+0x7d0/0x7d0 [ 43.563101] ? selinux_socket_sendmsg+0x36/0x40 [ 43.567741] ? security_socket_sendmsg+0x89/0xb0 [ 43.572474] ? inet_recvmsg+0x5f0/0x5f0 [ 43.576421] ? sock_sendmsg+0x4f/0x110 [ 43.580278] ? fput+0xd2/0x140 [ 43.583440] ? SYSC_sendto+0x40d/0x5a0 [ 43.587297] ? SYSC_connect+0x470/0x470 [ 43.591241] ? find_held_lock+0x35/0x1d0 [ 43.595273] ? exit_to_usermode_loop+0x98/0x300 [ 43.599916] exit_to_usermode_loop+0x224/0x300 [ 43.604469] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 43.609975] ? handle_mm_fault+0x4a2/0x860 [ 43.614175] ? down_read_trylock+0xdb/0x170 [ 43.618468] syscall_return_slowpath+0x3a7/0x450 [ 43.623202] ? prepare_exit_to_usermode+0x220/0x220 [ 43.628188] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 43.633090] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.638082] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 43.642811] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 43.647535] RIP: 0033:0x445469 [ 43.650690] RSP: 002b:00007f298f618db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 43.658364] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 43.665603] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 43.672841] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 43.680078] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 43.687314] R13: 00007fff1f068acf R14: 00007f298f6199c0 R15: 0000000000000000 [ 43.694749] Dumping ftrace buffer: [ 43.698302] (ftrace buffer empty) [ 43.701979] Kernel Offset: disabled [ 43.705589] Rebooting in 86400 seconds..