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-0,10.128.0.30' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 33.728115] refcount_t: underflow; use-after-free. [ 33.733196] ------------[ cut here ]------------ [ 33.738213] WARNING: CPU: 0 PID: 2946 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 33.746934] Kernel panic - not syncing: panic_on_warn set ... [ 33.746934] [ 33.754288] CPU: 0 PID: 2946 Comm: syzkaller695822 Not tainted 4.13.0-rc4-next-20170811 #1 [ 33.762673] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 33.772044] Call Trace: [ 33.774619] dump_stack+0x194/0x257 [ 33.778228] ? arch_local_irq_restore+0x53/0x53 [ 33.782886] panic+0x1e4/0x417 [ 33.786053] ? __warn+0x1d9/0x1d9 [ 33.789477] ? show_regs_print_info+0x65/0x65 [ 33.793970] ? refcount_sub_and_test+0x167/0x1b0 [ 33.798722] __warn+0x1c4/0x1d9 [ 33.801985] ? refcount_sub_and_test+0x167/0x1b0 [ 33.806725] report_bug+0x211/0x2d0 [ 33.810330] fixup_bug+0x40/0x90 [ 33.813673] do_trap+0x260/0x390 [ 33.817033] do_error_trap+0x120/0x390 [ 33.820925] ? do_trap+0x390/0x390 [ 33.824481] ? refcount_sub_and_test+0x167/0x1b0 [ 33.829229] ? vprintk_emit+0x3ea/0x590 [ 33.833235] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 33.838084] do_invalid_op+0x1b/0x20 [ 33.841806] invalid_op+0x1e/0x30 [ 33.845253] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 33.850600] RSP: 0018:ffff8801d201e300 EFLAGS: 00010282 [ 33.855954] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 33.863217] RDX: 0000000000000026 RSI: 1ffff1003a403c20 RDI: ffffed003a403c54 [ 33.870578] RBP: ffff8801d201e390 R08: 0000000000000001 R09: 0000000000000000 [ 33.877938] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a403c61 [ 33.885185] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d0c10a3c [ 33.892462] ? refcount_inc+0x50/0x50 [ 33.896250] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 33.900992] ? sctp_association_free+0x2d0/0x930 [ 33.905734] ? sctp_do_sm+0x28e7/0x6d90 [ 33.909690] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 33.914429] ? sctp_close+0x3c6/0x980 [ 33.918208] ? inet_release+0xed/0x1c0 [ 33.922092] sctp_wfree+0x183/0x620 [ 33.925721] ? __sctp_write_space+0x910/0x910 [ 33.930201] skb_release_head_state+0x124/0x200 [ 33.934864] skb_release_all+0x15/0x60 [ 33.938771] consume_skb+0x153/0x490 [ 33.942474] ? sctp_chunk_put+0x99/0x420 [ 33.946518] ? alloc_skb_with_frags+0x710/0x710 [ 33.951168] ? sctp_chunk_hold+0x20/0x20 [ 33.955211] ? refcount_sub_and_test+0x115/0x1b0 [ 33.959954] ? refcount_inc+0x50/0x50 [ 33.963740] ? mark_held_locks+0xaf/0x100 [ 33.967863] ? sctp_datamsg_put+0x456/0x560 [ 33.972177] sctp_chunk_put+0x29c/0x420 [ 33.976132] ? sctp_chunk_hold+0x20/0x20 [ 33.980173] ? sctp_transport_dst_confirm+0x50/0x50 [ 33.985174] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 33.990347] ? lock_release+0xa40/0xa40 [ 33.994304] ? __read_once_size_nocheck.constprop.8+0x10/0x10 [ 34.000178] ? entry_SYSCALL_64_fastpath+0xbc/0xbe [ 34.005080] ? bpf_prog_kallsyms_find+0xbd/0x440 [ 34.009816] ? show_initstate+0xb0/0xb0 [ 34.013767] sctp_chunk_free+0x53/0x60 [ 34.017642] __sctp_outq_teardown+0xc7d/0x15a0 [ 34.022212] ? lock_downgrade+0x990/0x990 [ 34.026343] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 34.031251] ? unwind_dump+0x4c0/0x4c0 [ 34.035127] ? is_bpf_text_address+0xa4/0x120 [ 34.039596] ? __kernel_text_address+0xae/0xe0 [ 34.044165] ? unwind_get_return_address+0x61/0xa0 [ 34.049080] ? __save_stack_trace+0x7e/0xd0 [ 34.053389] ? add_lock_to_list.isra.35+0x1ff/0x4f0 [ 34.058392] ? SOFTIRQ_verbose+0x10/0x10 [ 34.062445] ? save_stack_trace+0x16/0x20 [ 34.066580] ? check_noncircular+0x20/0x20 [ 34.070796] ? print_usage_bug+0x480/0x480 [ 34.075022] ? lock_acquire+0x1d5/0x580 [ 34.078971] ? lock_acquire+0x1d5/0x580 [ 34.082922] ? lock_timer_base+0x1a3/0x2b0 [ 34.087142] ? find_held_lock+0x35/0x1d0 [ 34.091189] ? sock_def_wakeup+0x1f9/0x350 [ 34.095404] ? lock_downgrade+0x990/0x990 [ 34.099535] ? lock_release+0xa40/0xa40 [ 34.103503] sctp_outq_free+0x15/0x20 [ 34.107291] sctp_association_free+0x2d0/0x930 [ 34.111853] ? sctp_asconf_queue_teardown+0x700/0x700 [ 34.117023] ? sock_def_wakeup+0x222/0x350 [ 34.121241] ? sk_dst_check+0x560/0x560 [ 34.125192] ? sctp_association_put+0x74/0x2f0 [ 34.129760] ? sctp_association_hold+0x20/0x20 [ 34.134322] ? __kernel_text_address+0xae/0xe0 [ 34.138888] ? unwind_get_return_address+0x61/0xa0 [ 34.143797] ? sctp_sm_lookup_event+0x95/0x3c0 [ 34.148363] sctp_do_sm+0x28e7/0x6d90 [ 34.152159] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 34.158197] ? save_stack_trace+0x16/0x20 [ 34.162326] ? kasan_slab_free+0x6e/0xc0 [ 34.166365] ? print_usage_bug+0x480/0x480 [ 34.170576] ? __lock_acquire+0x6aa/0x3bc0 [ 34.174790] ? print_usage_bug+0x480/0x480 [ 34.179008] ? __lock_acquire+0x6aa/0x3bc0 [ 34.183237] ? find_held_lock+0x35/0x1d0 [ 34.187283] ? skb_dequeue+0x12a/0x180 [ 34.191145] ? lock_downgrade+0x990/0x990 [ 34.195272] ? do_raw_spin_trylock+0x190/0x190 [ 34.199839] ? mark_held_locks+0xaf/0x100 [ 34.203984] ? trace_hardirqs_on+0xd/0x10 [ 34.208136] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 34.212706] sctp_close+0x3c6/0x980 [ 34.216325] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 34.221580] ? unwind_get_return_address+0x61/0xa0 [ 34.226496] ? check_noncircular+0x20/0x20 [ 34.230708] ? check_noncircular+0x20/0x20 [ 34.234937] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 34.239427] ? ipv6_sock_mc_close+0x148/0x1a0 [ 34.243918] ? ipv6_sock_ac_drop+0x580/0x580 [ 34.248306] ? ip_mc_drop_socket+0x1ce/0x230 [ 34.252690] ? __fsnotify_parent+0xb4/0x3a0 [ 34.256992] inet_release+0xed/0x1c0 [ 34.260690] inet6_release+0x50/0x70 [ 34.264376] sock_release+0x8d/0x1e0 [ 34.268075] ? sock_release+0x1e0/0x1e0 [ 34.272019] sock_close+0x16/0x20 [ 34.275450] __fput+0x327/0x7e0 [ 34.278723] ? fput+0x140/0x140 [ 34.281986] ? _raw_spin_unlock_irq+0x27/0x70 [ 34.286469] ____fput+0x15/0x20 [ 34.289735] task_work_run+0x199/0x270 [ 34.293602] ? task_work_cancel+0x210/0x210 [ 34.297905] ? _raw_spin_unlock+0x22/0x30 [ 34.302030] ? switch_task_namespaces+0x87/0xc0 [ 34.306690] do_exit+0xa4a/0x1b20 [ 34.310126] ? print_usage_bug+0x480/0x480 [ 34.314354] ? exit_notify+0xb10/0xb10 [ 34.318225] ? check_noncircular+0x20/0x20 [ 34.322445] ? check_noncircular+0x20/0x20 [ 34.326664] ? find_held_lock+0x35/0x1d0 [ 34.330709] ? find_held_lock+0x35/0x1d0 [ 34.334766] ? check_noncircular+0x20/0x20 [ 34.338985] ? check_noncircular+0x20/0x20 [ 34.343214] ? lock_downgrade+0x990/0x990 [ 34.347774] ? do_raw_spin_trylock+0x190/0x190 [ 34.352353] ? reacquire_held_locks+0x1fd/0x3d0 [ 34.357015] ? mark_held_locks+0xaf/0x100 [ 34.361151] ? reacquire_held_locks+0x1fd/0x3d0 [ 34.365802] ? check_noncircular+0x20/0x20 [ 34.370048] ? find_held_lock+0x35/0x1d0 [ 34.374096] ? release_sock+0x1d4/0x2a0 [ 34.378056] ? lock_downgrade+0x990/0x990 [ 34.382177] ? lock_downgrade+0x990/0x990 [ 34.386316] ? find_held_lock+0x35/0x1d0 [ 34.390370] ? get_signal+0x855/0x17e0 [ 34.394249] ? lock_downgrade+0x990/0x990 [ 34.398381] do_group_exit+0x149/0x400 [ 34.402252] ? __lock_is_held+0xb6/0x140 [ 34.406288] ? SyS_exit+0x30/0x30 [ 34.409729] ? _raw_spin_unlock_irq+0x27/0x70 [ 34.414205] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 34.419221] get_signal+0x7e8/0x17e0 [ 34.422940] ? ptrace_notify+0x130/0x130 [ 34.426983] ? __local_bh_enable_ip+0x9d/0x160 [ 34.431549] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 34.436553] ? release_sock+0x1d4/0x2a0 [ 34.440521] ? trace_hardirqs_on+0xd/0x10 [ 34.444744] ? __local_bh_enable_ip+0x9d/0x160 [ 34.449304] ? _raw_spin_unlock_bh+0x30/0x40 [ 34.453738] ? release_sock+0x1d4/0x2a0 [ 34.457724] ? trace_hardirqs_on+0xd/0x10 [ 34.461863] do_signal+0x94/0x1ee0 [ 34.465430] ? inet_sendmsg+0x11f/0x5e0 [ 34.469396] ? inet_sendmsg+0x126/0x5e0 [ 34.473357] ? __might_sleep+0x95/0x190 [ 34.477430] ? setup_sigcontext+0x7d0/0x7d0 [ 34.481749] ? selinux_socket_sendmsg+0x36/0x40 [ 34.486536] ? security_socket_sendmsg+0x89/0xb0 [ 34.491557] ? inet_recvmsg+0x5f0/0x5f0 [ 34.495690] ? sock_sendmsg+0x4f/0x110 [ 34.499575] ? fput+0xd2/0x140 [ 34.502780] ? SYSC_sendto+0x40d/0x5a0 [ 34.506660] ? SYSC_connect+0x470/0x470 [ 34.510631] ? find_held_lock+0x35/0x1d0 [ 34.514678] ? exit_to_usermode_loop+0x98/0x2d0 [ 34.520229] exit_to_usermode_loop+0x21c/0x2d0 [ 34.524809] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 34.530325] ? down_read_trylock+0xdb/0x170 [ 34.534622] ? __do_page_fault+0x2b8/0xb60 [ 34.538841] syscall_return_slowpath+0x42f/0x500 [ 34.543588] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 34.548600] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 34.553512] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 34.558510] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 34.563254] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 34.568332] RIP: 0033:0x445469 [ 34.571495] RSP: 002b:00007f1530d5fdb8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 34.579220] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 34.586569] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 34.593818] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 34.601065] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 34.608321] R13: 00007ffc4560f35f R14: 00007f1530d609c0 R15: 0000000000000000 [ 34.616012] Dumping ftrace buffer: [ 34.619617] (ftrace buffer empty) [ 34.623303] Kernel Offset: disabled [ 34.626901] Rebooting in 86400 seconds..