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..