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-8,10.128.0.61' (ECDSA) to the list of known hosts.
executing program
syzkaller login: [   34.610522] refcount_t: underflow; use-after-free.
[   34.611401] ------------[ cut here ]------------
[   34.612189] WARNING: CPU: 0 PID: 2949 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0
[   34.613401] Kernel panic - not syncing: panic_on_warn set ...
[   34.613401] 
[   34.614388] CPU: 0 PID: 2949 Comm: syzkaller970187 Not tainted 4.13.0-rc4-next-20170811 #1
[   34.615482] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   34.616697] Call Trace:
[   34.617078]  dump_stack+0x194/0x257
[   34.617607]  ? arch_local_irq_restore+0x53/0x53
[   34.618258]  panic+0x1e4/0x417
[   34.618697]  ? __warn+0x1d9/0x1d9
[   34.619170]  ? show_regs_print_info+0x65/0x65
[   34.619798]  ? refcount_sub_and_test+0x167/0x1b0
[   34.620427]  __warn+0x1c4/0x1d9
[   34.620881]  ? refcount_sub_and_test+0x167/0x1b0
[   34.621514]  report_bug+0x211/0x2d0
[   34.622006]  fixup_bug+0x40/0x90
[   34.622457]  do_trap+0x260/0x390
[   34.622919]  do_error_trap+0x120/0x390
[   34.623472]  ? do_trap+0x390/0x390
[   34.623966]  ? refcount_sub_and_test+0x167/0x1b0
[   34.624596]  ? vprintk_emit+0x3ea/0x590
[   34.625132]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   34.625778]  do_invalid_op+0x1b/0x20
[   34.626274]  invalid_op+0x1e/0x30
[   34.626756] RIP: 0010:refcount_sub_and_test+0x167/0x1b0
[   34.627478] RSP: 0018:ffff8801d0bc6300 EFLAGS: 00010282
[   34.628185] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000
[   34.629134] RDX: 0000000000000026 RSI: 1ffff1003a178c20 RDI: ffffed003a178c54
[   34.630082] RBP: ffff8801d0bc6390 R08: 0000000000000001 R09: 0000000000000000
[   34.633472] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a178c61
[   34.640707] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d459aa3c
[   34.647974]  ? refcount_inc+0x50/0x50
[   34.651747]  ? __sctp_outq_teardown+0xc7d/0x15a0
[   34.656478]  ? sctp_association_free+0x2d0/0x930
[   34.661203]  ? sctp_do_sm+0x28e7/0x6d90
[   34.665147]  ? sctp_primitive_SHUTDOWN+0xa0/0xd0
[   34.669868]  ? sctp_close+0x3c6/0x980
[   34.673632]  ? inet_release+0xed/0x1c0
[   34.677492]  sctp_wfree+0x183/0x620
[   34.681089]  ? __sctp_write_space+0x910/0x910
[   34.685554]  skb_release_head_state+0x124/0x200
[   34.690193]  skb_release_all+0x15/0x60
[   34.694048]  consume_skb+0x153/0x490
[   34.697730]  ? sctp_chunk_put+0x99/0x420
[   34.701761]  ? alloc_skb_with_frags+0x710/0x710
[   34.706421]  ? sctp_chunk_hold+0x20/0x20
[   34.710457]  ? refcount_sub_and_test+0x115/0x1b0
[   34.715185]  ? refcount_inc+0x50/0x50
[   34.718959]  ? mark_held_locks+0xaf/0x100
[   34.723084]  ? sctp_datamsg_put+0x456/0x560
[   34.727379]  sctp_chunk_put+0x29c/0x420
[   34.731321]  ? sctp_chunk_hold+0x20/0x20
[   34.735392]  ? sctp_transport_dst_confirm+0x50/0x50
[   34.740382]  ? debug_check_no_locks_freed+0x3c0/0x3c0
[   34.745541]  ? lock_release+0xa40/0xa40
[   34.749480]  ? __read_once_size_nocheck.constprop.8+0x10/0x10
[   34.755331]  ? entry_SYSCALL_64_fastpath+0xbc/0xbe
[   34.760225]  ? bpf_prog_kallsyms_find+0xbd/0x440
[   34.764946]  ? show_initstate+0xb0/0xb0
[   34.768890]  sctp_chunk_free+0x53/0x60
[   34.772749]  __sctp_outq_teardown+0xc7d/0x15a0
[   34.777296]  ? lock_downgrade+0x990/0x990
[   34.781420]  ? sctp_inq_set_th_handler+0x1b0/0x1b0
[   34.786318]  ? unwind_dump+0x4c0/0x4c0
[   34.790185]  ? is_bpf_text_address+0xa4/0x120
[   34.794649]  ? __kernel_text_address+0xae/0xe0
[   34.799197]  ? unwind_get_return_address+0x61/0xa0
[   34.804094]  ? __save_stack_trace+0x7e/0xd0
[   34.808385]  ? add_lock_to_list.isra.35+0x1ff/0x4f0
[   34.813370]  ? SOFTIRQ_verbose+0x10/0x10
[   34.817399]  ? save_stack_trace+0x16/0x20
[   34.821518]  ? check_noncircular+0x20/0x20
[   34.825719]  ? print_usage_bug+0x480/0x480
[   34.829933]  ? lock_acquire+0x1d5/0x580
[   34.833870]  ? lock_acquire+0x1d5/0x580
[   34.837810]  ? lock_timer_base+0x1a3/0x2b0
[   34.842012]  ? find_held_lock+0x35/0x1d0
[   34.846049]  ? sock_def_wakeup+0x1f9/0x350
[   34.850250]  ? lock_downgrade+0x990/0x990
[   34.854364]  ? lock_release+0xa40/0xa40
[   34.858310]  sctp_outq_free+0x15/0x20
[   34.862081]  sctp_association_free+0x2d0/0x930
[   34.866635]  ? sctp_asconf_queue_teardown+0x700/0x700
[   34.871796]  ? sock_def_wakeup+0x222/0x350
[   34.876002]  ? sk_dst_check+0x560/0x560
[   34.879957]  ? sctp_association_put+0x74/0x2f0
[   34.884504]  ? sctp_association_hold+0x20/0x20
[   34.889059]  ? sctp_sm_lookup_event+0x95/0x3c0
[   34.893611]  sctp_do_sm+0x28e7/0x6d90
[   34.897395]  ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0
[   34.903421]  ? __lock_acquire+0x6aa/0x3bc0
[   34.907628]  ? print_usage_bug+0x480/0x480
[   34.911833]  ? print_usage_bug+0x480/0x480
[   34.916045]  ? debug_check_no_locks_freed+0x3c0/0x3c0
[   34.921212]  ? depot_save_stack+0x3b5/0x490
[   34.925507]  ? find_held_lock+0x35/0x1d0
[   34.929547]  ? skb_dequeue+0x12a/0x180
[   34.933405]  ? lock_downgrade+0x990/0x990
[   34.937535]  ? do_raw_spin_trylock+0x190/0x190
[   34.942094]  ? mark_held_locks+0xaf/0x100
[   34.946217]  ? trace_hardirqs_on+0xd/0x10
[   34.950341]  sctp_primitive_SHUTDOWN+0xa0/0xd0
[   34.954901]  sctp_close+0x3c6/0x980
[   34.958505]  ? sctp_apply_peer_addr_params+0xf30/0xf30
[   34.963764]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   34.968756]  ? trace_hardirqs_on+0xd/0x10
[   34.972883]  ? rcu_eqs_enter_common.constprop.73+0x270/0x270
[   34.978657]  ? ipv6_sock_ac_close+0x2e8/0x3e0
[   34.983121]  ? ipv6_sock_mc_close+0x148/0x1a0
[   34.987586]  ? ipv6_sock_ac_drop+0x580/0x580
[   34.991964]  ? ip_mc_drop_socket+0x1ce/0x230
[   34.996345]  ? __fsnotify_parent+0xb4/0x3a0
[   35.000639]  inet_release+0xed/0x1c0
[   35.004326]  inet6_release+0x50/0x70
[   35.008010]  sock_release+0x8d/0x1e0
[   35.011690]  ? sock_release+0x1e0/0x1e0
[   35.015632]  sock_close+0x16/0x20
[   35.019055]  __fput+0x327/0x7e0
[   35.022306]  ? fput+0x140/0x140
[   35.025552]  ? check_same_owner+0x320/0x320
[   35.029856]  ____fput+0x15/0x20
[   35.033104]  task_work_run+0x199/0x270
[   35.036966]  ? task_work_cancel+0x210/0x210
[   35.041267]  ? free_nsproxy+0x185/0x1f0
[   35.045208]  ? switch_task_namespaces+0xa2/0xc0
[   35.049852]  do_exit+0xa4a/0x1b20
[   35.053277]  ? print_usage_bug+0x480/0x480
[   35.057489]  ? exit_notify+0xb10/0xb10
[   35.061345]  ? check_noncircular+0x20/0x20
[   35.065546]  ? check_noncircular+0x20/0x20
[   35.069748]  ? find_held_lock+0x35/0x1d0
[   35.073781]  ? find_held_lock+0x35/0x1d0
[   35.077816]  ? check_noncircular+0x20/0x20
[   35.082019]  ? check_noncircular+0x20/0x20
[   35.086219]  ? lock_downgrade+0x990/0x990
[   35.090335]  ? do_raw_spin_trylock+0x190/0x190
[   35.094888]  ? reacquire_held_locks+0x1fd/0x3d0
[   35.099525]  ? mark_held_locks+0xaf/0x100
[   35.103637]  ? reacquire_held_locks+0x1fd/0x3d0
[   35.108275]  ? check_noncircular+0x20/0x20
[   35.112475]  ? find_held_lock+0x35/0x1d0
[   35.116512]  ? release_sock+0x1d4/0x2a0
[   35.120456]  ? lock_downgrade+0x990/0x990
[   35.124572]  ? lock_downgrade+0x990/0x990
[   35.128687]  ? find_held_lock+0x35/0x1d0
[   35.132718]  ? get_signal+0x855/0x17e0
[   35.136572]  ? lock_downgrade+0x990/0x990
[   35.140694]  do_group_exit+0x149/0x400
[   35.144555]  ? __lock_is_held+0xb6/0x140
[   35.148578]  ? SyS_exit+0x30/0x30
[   35.151996]  ? _raw_spin_unlock_irq+0x27/0x70
[   35.156467]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   35.161463]  get_signal+0x7e8/0x17e0
[   35.165167]  ? ptrace_notify+0x130/0x130
[   35.169213]  ? __local_bh_enable_ip+0x9d/0x160
[   35.173763]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   35.178744]  ? release_sock+0x1d4/0x2a0
[   35.182681]  ? trace_hardirqs_on+0xd/0x10
[   35.186795]  ? __local_bh_enable_ip+0x9d/0x160
[   35.191341]  ? _raw_spin_unlock_bh+0x30/0x40
[   35.195712]  ? release_sock+0x1d4/0x2a0
[   35.199652]  ? __release_sock+0x360/0x360
[   35.203766]  ? trace_hardirqs_on+0xd/0x10
[   35.207885]  do_signal+0x94/0x1ee0
[   35.211396]  ? inet_sendmsg+0x11f/0x5e0
[   35.215331]  ? inet_sendmsg+0x126/0x5e0
[   35.219286]  ? __might_sleep+0x95/0x190
[   35.223234]  ? setup_sigcontext+0x7d0/0x7d0
[   35.227522]  ? selinux_socket_sendmsg+0x36/0x40
[   35.232162]  ? security_socket_sendmsg+0x89/0xb0
[   35.236889]  ? inet_recvmsg+0x5f0/0x5f0
[   35.240830]  ? sock_sendmsg+0x4f/0x110
[   35.244685]  ? fput+0xd2/0x140
[   35.247843]  ? SYSC_sendto+0x40d/0x5a0
[   35.251702]  ? SYSC_connect+0x470/0x470
[   35.255645]  ? find_held_lock+0x35/0x1d0
[   35.259685]  ? exit_to_usermode_loop+0x98/0x2d0
[   35.264334]  exit_to_usermode_loop+0x21c/0x2d0
[   35.268884]  ? trace_event_raw_event_sys_exit+0x260/0x260
[   35.274389]  ? down_read_trylock+0xdb/0x170
[   35.278676]  ? __do_page_fault+0x2b8/0xb60
[   35.282979]  syscall_return_slowpath+0x42f/0x500
[   35.287703]  ? prepare_exit_to_usermode+0x2c0/0x2c0
[   35.292685]  ? entry_SYSCALL_64_fastpath+0x91/0xbe
[   35.297582]  ? trace_hardirqs_on_caller+0x421/0x5c0
[   35.302569]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[   35.307311]  entry_SYSCALL_64_fastpath+0xbc/0xbe
[   35.312038] RIP: 0033:0x445dd9
[   35.315211] RSP: 002b:00007f13a013cdb8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c
[   35.322889] RAX: 0000000000000005 RBX: 0000000000000000 RCX: 0000000000445dd9
[   35.330132] RDX: 0000000000000005 RSI: 0000000020fe7000 RDI: 0000000000000003
[   35.337379] RBP: 0000000000000000 R08: 0000000020fe7ff0 R09: 0000000000000010
[   35.344964] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
[   35.352218] R13: 00000000007efe8f R14: 00007f13a013d9c0 R15: 0000000000000000
[   35.359898] Dumping ftrace buffer:
[   35.363474]    (ftrace buffer empty)
[   35.367152] Kernel Offset: disabled
[   35.370750] Rebooting in 86400 seconds..