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-9,10.128.0.28' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.654266] refcount_t: underflow; use-after-free. [ 41.659981] ------------[ cut here ]------------ [ 41.664894] WARNING: CPU: 0 PID: 3060 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 41.673567] Kernel panic - not syncing: panic_on_warn set ... [ 41.673567] [ 41.680910] CPU: 0 PID: 3060 Comm: syzkaller316326 Not tainted 4.13.0-rc6-next-20170828+ #10 [ 41.689457] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.698795] Call Trace: [ 41.701360] dump_stack+0x194/0x257 [ 41.704981] ? arch_local_irq_restore+0x53/0x53 [ 41.709641] panic+0x1e4/0x41c [ 41.712808] ? refcount_error_report+0x214/0x214 [ 41.717539] ? show_regs_print_info+0x65/0x65 [ 41.722036] ? refcount_sub_and_test+0x167/0x1b0 [ 41.726766] __warn+0x1c4/0x1e0 [ 41.730021] ? refcount_sub_and_test+0x167/0x1b0 [ 41.734759] report_bug+0x211/0x2d0 [ 41.738365] fixup_bug+0x40/0x90 [ 41.741706] do_trap+0x260/0x390 [ 41.745051] do_error_trap+0x120/0x390 [ 41.748918] ? do_trap+0x390/0x390 [ 41.752443] ? refcount_sub_and_test+0x167/0x1b0 [ 41.757172] ? vprintk_emit+0x3ea/0x590 [ 41.761130] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.765954] do_invalid_op+0x1b/0x20 [ 41.769661] invalid_op+0x18/0x20 [ 41.773096] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 41.778439] RSP: 0018:ffff8801d5706320 EFLAGS: 00010286 [ 41.783777] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 41.791018] RDX: 0000000000000026 RSI: 1ffff1003aae0c24 RDI: ffffed003aae0c58 [ 41.798273] RBP: ffff8801d57063b0 R08: ffff8801d5705a10 R09: 0000000000000000 [ 41.805517] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003aae0c65 [ 41.812761] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801cc6b8a24 [ 41.820032] ? refcount_inc+0x50/0x50 [ 41.823806] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 41.828532] ? sctp_association_free+0x2d0/0x930 [ 41.833264] ? sctp_do_sm+0x28e7/0x6dd0 [ 41.837211] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.841937] ? sctp_close+0x3c6/0x980 [ 41.845714] ? inet_release+0xed/0x1c0 [ 41.849584] sctp_wfree+0x183/0x620 [ 41.853187] ? __sctp_write_space+0x910/0x910 [ 41.857661] skb_release_head_state+0x124/0x200 [ 41.862305] skb_release_all+0x15/0x60 [ 41.866167] consume_skb+0x153/0x490 [ 41.869852] ? sctp_chunk_put+0x99/0x420 [ 41.873889] ? alloc_skb_with_frags+0x710/0x710 [ 41.878543] ? sctp_chunk_hold+0x20/0x20 [ 41.882585] ? refcount_sub_and_test+0x115/0x1b0 [ 41.887324] ? refcount_inc+0x50/0x50 [ 41.891107] ? mark_held_locks+0xb2/0x100 [ 41.895230] ? sctp_datamsg_put+0x456/0x560 [ 41.899548] sctp_chunk_put+0x29c/0x420 [ 41.903524] ? sctp_chunk_hold+0x20/0x20 [ 41.907560] ? sctp_transport_dst_confirm+0x50/0x50 [ 41.912553] ? unwind_dump+0x4c0/0x4c0 [ 41.916415] ? unwind_dump+0x4c0/0x4c0 [ 41.920283] sctp_chunk_free+0x53/0x60 [ 41.924155] __sctp_outq_teardown+0xc7d/0x15a0 [ 41.928719] ? sock_release+0x8d/0x1e0 [ 41.932586] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 41.937505] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.942498] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.947489] ? unwind_dump+0x4c0/0x4c0 [ 41.951349] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 41.956342] ? unwind_dump+0x4c0/0x4c0 [ 41.960216] ? check_noncircular+0x20/0x20 [ 41.964433] ? check_noncircular+0x20/0x20 [ 41.968642] ? unwind_get_return_address+0x61/0xa0 [ 41.973545] ? __save_stack_trace+0x61/0xd0 [ 41.977841] ? check_noncircular+0x20/0x20 [ 41.982052] ? print_usage_bug+0x480/0x480 [ 41.986268] ? find_held_lock+0x39/0x1d0 [ 41.990315] ? lock_downgrade+0x990/0x990 [ 41.994447] ? sk_dst_check+0x560/0x560 [ 41.998397] ? rcu_read_lock_sched_held+0x108/0x120 [ 42.003390] ? lock_release+0xd70/0xd70 [ 42.007350] sctp_outq_free+0x15/0x20 [ 42.011129] sctp_association_free+0x2d0/0x930 [ 42.015703] ? sctp_asconf_queue_teardown+0x700/0x700 [ 42.020873] ? sock_def_wakeup+0x222/0x350 [ 42.025086] ? sk_dst_check+0x560/0x560 [ 42.029038] ? sctp_association_put+0x74/0x2f0 [ 42.033599] ? sctp_association_hold+0x20/0x20 [ 42.038165] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 42.043337] ? find_held_lock+0x39/0x1d0 [ 42.047374] ? sctp_sm_lookup_event+0x95/0x3c0 [ 42.051935] sctp_do_sm+0x28e7/0x6dd0 [ 42.055731] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 42.061788] ? print_usage_bug+0x480/0x480 [ 42.066010] ? do_raw_spin_trylock+0x190/0x190 [ 42.070567] ? print_usage_bug+0x480/0x480 [ 42.074782] ? find_held_lock+0x39/0x1d0 [ 42.078830] ? lock_downgrade+0x990/0x990 [ 42.082976] ? skb_dequeue+0x22/0x180 [ 42.086782] ? do_raw_spin_trylock+0x190/0x190 [ 42.091351] ? mark_held_locks+0xb2/0x100 [ 42.095480] ? trace_hardirqs_on+0xd/0x10 [ 42.099609] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.104169] sctp_close+0x3c6/0x980 [ 42.107781] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 42.113033] ? dentry_free+0xcd/0x130 [ 42.116809] ? rcu_read_lock_sched_held+0x108/0x120 [ 42.121813] ? kmem_cache_free+0x249/0x280 [ 42.126038] ? dentry_free+0xd2/0x130 [ 42.129832] ? locks_remove_file+0x3fa/0x5a0 [ 42.134228] ? fcntl_setlk+0x10d0/0x10d0 [ 42.138279] ? __fsnotify_parent+0xb4/0x3a0 [ 42.142576] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.146964] inet_release+0xed/0x1c0 [ 42.150656] sock_release+0x8d/0x1e0 [ 42.154357] ? sock_release+0x1e0/0x1e0 [ 42.158307] sock_close+0x16/0x20 [ 42.161735] __fput+0x333/0x7f0 [ 42.164997] ? fput+0x140/0x140 [ 42.168256] ? check_same_owner+0x320/0x320 [ 42.172554] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.177044] ____fput+0x15/0x20 [ 42.180301] task_work_run+0x199/0x270 [ 42.184200] ? task_work_cancel+0x210/0x210 [ 42.188513] ? _raw_spin_unlock+0x22/0x30 [ 42.192638] ? switch_task_namespaces+0x87/0xc0 [ 42.197287] do_exit+0xa52/0x1b40 [ 42.200748] ? print_usage_bug+0x480/0x480 [ 42.204972] ? mm_update_next_owner+0x930/0x930 [ 42.209620] ? find_held_lock+0x39/0x1d0 [ 42.213660] ? check_noncircular+0x20/0x20 [ 42.217867] ? check_noncircular+0x20/0x20 [ 42.222090] ? lock_downgrade+0x990/0x990 [ 42.226214] ? osq_unlock+0x350/0x350 [ 42.229999] ? reacquire_held_locks+0x205/0x3d0 [ 42.234642] ? check_noncircular+0x20/0x20 [ 42.238851] ? find_held_lock+0x39/0x1d0 [ 42.242925] ? lock_downgrade+0x990/0x990 [ 42.247050] ? lock_downgrade+0x990/0x990 [ 42.251176] ? find_held_lock+0x39/0x1d0 [ 42.255220] ? lock_downgrade+0x990/0x990 [ 42.259343] ? recalc_sigpending_tsk+0x117/0x150 [ 42.264076] ? recalc_sigpending+0x103/0x160 [ 42.268468] ? recalc_sigpending_tsk+0x150/0x150 [ 42.273196] ? get_signal+0x397/0x17e0 [ 42.277069] do_group_exit+0x149/0x400 [ 42.280934] ? __lock_is_held+0xbc/0x140 [ 42.284970] ? SyS_exit+0x30/0x30 [ 42.288399] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.292885] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.297898] get_signal+0x7e8/0x17e0 [ 42.301620] ? ptrace_notify+0x130/0x130 [ 42.305658] ? __local_bh_enable_ip+0x9d/0x160 [ 42.310216] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.315220] ? release_sock+0x1d4/0x2a0 [ 42.319169] ? trace_hardirqs_on+0xd/0x10 [ 42.323302] ? __local_bh_enable_ip+0x9d/0x160 [ 42.327861] ? _raw_spin_unlock_bh+0x30/0x40 [ 42.332244] ? release_sock+0x1d4/0x2a0 [ 42.336194] ? __release_sock+0x360/0x360 [ 42.340324] ? trace_hardirqs_on+0xd/0x10 [ 42.344453] do_signal+0x94/0x1ee0 [ 42.347974] ? inet_sendmsg+0x11f/0x5e0 [ 42.351921] ? inet_sendmsg+0x126/0x5e0 [ 42.355869] ? __might_sleep+0x95/0x190 [ 42.359828] ? setup_sigcontext+0x7d0/0x7d0 [ 42.364127] ? selinux_socket_sendmsg+0x36/0x40 [ 42.368776] ? security_socket_sendmsg+0x89/0xb0 [ 42.373505] ? inet_recvmsg+0x5f0/0x5f0 [ 42.377457] ? sock_sendmsg+0x4f/0x110 [ 42.381325] ? fput+0xd2/0x140 [ 42.384492] ? SYSC_sendto+0x413/0x5a0 [ 42.388356] ? SYSC_connect+0x480/0x480 [ 42.392311] ? lock_downgrade+0x990/0x990 [ 42.396434] ? exit_to_usermode_loop+0x98/0x300 [ 42.401084] exit_to_usermode_loop+0x224/0x300 [ 42.405669] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 42.411183] ? handle_mm_fault+0x4a2/0x860 [ 42.415398] syscall_return_slowpath+0x42f/0x500 [ 42.420130] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 42.425133] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 42.430048] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.435045] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.439781] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 42.444507] RIP: 0033:0x4473f9 [ 42.447668] RSP: 002b:00007f8fb7c84db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 42.455349] RAX: 000000000000001a RBX: 0000000000000000 RCX: 00000000004473f9 [ 42.462594] RDX: 000000000000001a RSI: 0000000020b54fe6 RDI: 0000000000000005 [ 42.469835] RBP: 0000000000000000 R08: 0000000020b54000 R09: 0000000000000010 [ 42.477080] R10: 0000000000000004 R11: 0000000000000212 R12: 0000000000000000 [ 42.484323] R13: 00000000007efd5f R14: 00007f8fb7c859c0 R15: 0000000000000000 [ 42.492016] Dumping ftrace buffer: [ 42.495577] (ftrace buffer empty) [ 42.499261] Kernel Offset: disabled [ 42.502887] Rebooting in 86400 seconds..