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-9,10.128.0.38' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 42.124755] refcount_t: underflow; use-after-free. [ 42.125658] ------------[ cut here ]------------ [ 42.126491] WARNING: CPU: 0 PID: 3003 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 42.127644] Kernel panic - not syncing: panic_on_warn set ... [ 42.127644] [ 42.128616] CPU: 0 PID: 3003 Comm: syzkaller145137 Not tainted 4.13.0-rc5+ #43 [ 42.129631] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.130874] Call Trace: [ 42.131249] dump_stack+0x194/0x257 [ 42.131747] ? arch_local_irq_restore+0x53/0x53 [ 42.132381] panic+0x1e4/0x417 [ 42.132815] ? __warn+0x1d9/0x1d9 [ 42.133283] ? show_regs_print_info+0x65/0x65 [ 42.134030] ? refcount_sub_and_test+0x167/0x1b0 [ 42.134663] __warn+0x1c4/0x1d9 [ 42.135105] ? refcount_sub_and_test+0x167/0x1b0 [ 42.135760] report_bug+0x211/0x2d0 [ 42.136290] fixup_bug+0x40/0x90 [ 42.136746] do_trap+0x260/0x390 [ 42.137253] do_error_trap+0x120/0x390 [ 42.137779] ? do_trap+0x390/0x390 [ 42.138256] ? refcount_sub_and_test+0x167/0x1b0 [ 42.138889] ? vprintk_emit+0x3ea/0x590 [ 42.139431] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.140080] do_invalid_op+0x1b/0x20 [ 42.140579] invalid_op+0x1e/0x30 [ 42.141098] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 42.141817] RSP: 0018:ffff8801d0176310 EFLAGS: 00010282 [ 42.142565] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 42.143545] RDX: 0000000000000026 RSI: 1ffff1003a02ec22 RDI: ffffed003a02ec56 [ 42.144569] RBP: ffff8801d01763a0 R08: 0000000000000001 R09: 0000000000000000 [ 42.145521] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a02ec63 [ 42.152758] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d01d1a3c [ 42.160016] ? refcount_inc+0x50/0x50 [ 42.163793] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 42.168515] ? sctp_association_free+0x2d0/0x930 [ 42.173237] ? sctp_do_sm+0x28e7/0x6d90 [ 42.177178] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.181897] ? sctp_close+0x3c6/0x980 [ 42.185665] ? inet_release+0xed/0x1c0 [ 42.189522] sctp_wfree+0x183/0x620 [ 42.193117] ? __sctp_write_space+0x910/0x910 [ 42.197586] skb_release_head_state+0x124/0x200 [ 42.202242] skb_release_all+0x15/0x60 [ 42.206108] consume_skb+0x153/0x490 [ 42.209797] ? sctp_chunk_put+0x99/0x420 [ 42.213830] ? pskb_carve+0x1db0/0x1db0 [ 42.217781] ? sctp_chunk_hold+0x20/0x20 [ 42.221822] ? refcount_sub_and_test+0x115/0x1b0 [ 42.226550] ? refcount_inc+0x50/0x50 [ 42.230319] ? mark_held_locks+0xaf/0x100 [ 42.234439] ? sctp_datamsg_put+0x456/0x560 [ 42.238735] sctp_chunk_put+0x29c/0x420 [ 42.242678] ? sctp_chunk_hold+0x20/0x20 [ 42.246709] ? sctp_transport_dst_confirm+0x50/0x50 [ 42.251696] ? noop_count+0x40/0x40 [ 42.255299] sctp_chunk_free+0x53/0x60 [ 42.259156] __sctp_outq_teardown+0xc7d/0x15a0 [ 42.263711] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 42.268606] ? lock_downgrade+0x990/0x990 [ 42.272736] ? lock_release+0xa40/0xa40 [ 42.276684] ? __free_insn_slot+0x5c0/0x5c0 [ 42.280986] ? update_stack_state+0x700/0x700 [ 42.285451] ? print_usage_bug+0x480/0x480 [ 42.289666] ? is_bpf_text_address+0xa4/0x120 [ 42.294141] ? __kernel_text_address+0xae/0xe0 [ 42.298709] ? unwind_get_return_address+0x61/0xa0 [ 42.303621] ? __save_stack_trace+0x7e/0xd0 [ 42.307915] ? check_noncircular+0x20/0x20 [ 42.312118] ? print_usage_bug+0x480/0x480 [ 42.316329] ? SOFTIRQ_verbose+0x10/0x10 [ 42.320360] ? save_stack_trace+0x16/0x20 [ 42.324476] ? save_trace+0x11f/0x350 [ 42.328258] ? lock_acquire+0x1d5/0x580 [ 42.332197] ? lock_acquire+0x1d5/0x580 [ 42.336143] ? lock_timer_base+0x1a3/0x2b0 [ 42.340349] ? find_held_lock+0x35/0x1d0 [ 42.344386] ? sock_def_wakeup+0x1f9/0x350 [ 42.348595] ? lock_downgrade+0x990/0x990 [ 42.352716] ? lock_release+0xa40/0xa40 [ 42.356673] sctp_outq_free+0x15/0x20 [ 42.360445] sctp_association_free+0x2d0/0x930 [ 42.365007] ? sctp_asconf_queue_teardown+0x700/0x700 [ 42.370172] ? sock_def_wakeup+0x222/0x350 [ 42.374380] ? sk_dst_check+0x560/0x560 [ 42.378326] ? sctp_association_put+0x74/0x2f0 [ 42.382877] ? sctp_association_hold+0x20/0x20 [ 42.387429] ? print_usage_bug+0x480/0x480 [ 42.391634] ? sctp_sm_lookup_event+0x95/0x3c0 [ 42.396191] sctp_do_sm+0x28e7/0x6d90 [ 42.399960] ? check_noncircular+0x20/0x20 [ 42.404173] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 42.410207] ? print_usage_bug+0x480/0x480 [ 42.414424] ? exit_to_usermode_loop+0x224/0x300 [ 42.419145] ? syscall_return_slowpath+0x3a7/0x450 [ 42.424042] ? print_usage_bug+0x480/0x480 [ 42.428259] ? find_held_lock+0x35/0x1d0 [ 42.432312] ? find_held_lock+0x35/0x1d0 [ 42.436354] ? skb_dequeue+0x12a/0x180 [ 42.440216] ? lock_downgrade+0x990/0x990 [ 42.444350] ? do_raw_spin_trylock+0x190/0x190 [ 42.448909] ? mark_held_locks+0xaf/0x100 [ 42.453032] ? trace_hardirqs_on+0xd/0x10 [ 42.457161] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.461725] sctp_close+0x3c6/0x980 [ 42.465328] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 42.470575] ? unwind_get_return_address+0x61/0xa0 [ 42.475571] ? trace_hardirqs_off+0xd/0x10 [ 42.479776] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 42.484849] ? check_noncircular+0x20/0x20 [ 42.489061] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 42.493530] ? ipv6_sock_mc_close+0x148/0x1a0 [ 42.497993] ? ipv6_sock_ac_drop+0x580/0x580 [ 42.502368] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.506744] ? __fsnotify_parent+0xb4/0x3a0 [ 42.511046] inet_release+0xed/0x1c0 [ 42.514730] inet6_release+0x50/0x70 [ 42.518411] sock_release+0x8d/0x1e0 [ 42.522090] ? sock_release+0x1e0/0x1e0 [ 42.526026] sock_close+0x16/0x20 [ 42.529448] __fput+0x327/0x7e0 [ 42.532700] ? fput+0x140/0x140 [ 42.535948] ? do_raw_spin_trylock+0x190/0x190 [ 42.540501] ? check_same_owner+0x320/0x320 [ 42.544790] ____fput+0x15/0x20 [ 42.548038] task_work_run+0x18a/0x260 [ 42.551893] ? task_work_cancel+0x210/0x210 [ 42.556186] ? _raw_spin_unlock+0x22/0x30 [ 42.560299] ? switch_task_namespaces+0x87/0xc0 [ 42.564940] do_exit+0xa3a/0x1b10 [ 42.568361] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 42.573520] ? print_usage_bug+0x480/0x480 [ 42.577728] ? mm_update_next_owner+0x930/0x930 [ 42.582360] ? check_noncircular+0x20/0x20 [ 42.586559] ? check_noncircular+0x20/0x20 [ 42.590764] ? find_held_lock+0x35/0x1d0 [ 42.594792] ? find_held_lock+0x35/0x1d0 [ 42.598822] ? check_noncircular+0x20/0x20 [ 42.603021] ? check_noncircular+0x20/0x20 [ 42.607220] ? lock_downgrade+0x990/0x990 [ 42.611338] ? do_raw_spin_trylock+0x190/0x190 [ 42.615888] ? reacquire_held_locks+0x1fd/0x3d0 [ 42.620531] ? mark_held_locks+0xaf/0x100 [ 42.624650] ? reacquire_held_locks+0x1fd/0x3d0 [ 42.629287] ? check_noncircular+0x20/0x20 [ 42.633490] ? find_held_lock+0x35/0x1d0 [ 42.637532] ? release_sock+0x1d4/0x2a0 [ 42.641474] ? lock_downgrade+0x990/0x990 [ 42.645588] ? lock_downgrade+0x990/0x990 [ 42.649707] ? find_held_lock+0x35/0x1d0 [ 42.653741] ? get_signal+0x855/0x17e0 [ 42.657595] ? lock_downgrade+0x990/0x990 [ 42.661715] do_group_exit+0x149/0x400 [ 42.665572] ? __lock_is_held+0xb6/0x140 [ 42.669599] ? SyS_exit+0x30/0x30 [ 42.673024] ? _raw_spin_unlock_irq+0x27/0x70 [ 42.677488] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.682482] get_signal+0x7e8/0x17e0 [ 42.686186] ? ptrace_notify+0x130/0x130 [ 42.690213] ? inet_autobind+0x1f/0x180 [ 42.694155] ? __local_bh_enable_ip+0x9d/0x160 [ 42.698707] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.703692] ? release_sock+0x1d4/0x2a0 [ 42.707630] ? trace_hardirqs_on+0xd/0x10 [ 42.711741] ? __local_bh_enable_ip+0x9d/0x160 [ 42.716291] ? _raw_spin_unlock_bh+0x30/0x40 [ 42.720665] ? release_sock+0x1d4/0x2a0 [ 42.724610] ? trace_hardirqs_on+0xd/0x10 [ 42.728739] do_signal+0x94/0x1ee0 [ 42.732249] ? inet_sendmsg+0x11f/0x5e0 [ 42.736189] ? inet_sendmsg+0x126/0x5e0 [ 42.740130] ? __might_sleep+0x95/0x190 [ 42.744073] ? setup_sigcontext+0x7d0/0x7d0 [ 42.748362] ? selinux_socket_sendmsg+0x36/0x40 [ 42.752996] ? security_socket_sendmsg+0x89/0xb0 [ 42.757729] ? inet_recvmsg+0x5f0/0x5f0 [ 42.761671] ? sock_sendmsg+0x4f/0x110 [ 42.765525] ? fput+0xd2/0x140 [ 42.768684] ? SYSC_sendto+0x40d/0x5a0 [ 42.772539] ? SYSC_connect+0x470/0x470 [ 42.776482] ? find_held_lock+0x35/0x1d0 [ 42.780512] ? exit_to_usermode_loop+0x98/0x300 [ 42.785155] exit_to_usermode_loop+0x224/0x300 [ 42.789714] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 42.795227] ? handle_mm_fault+0x4a2/0x860 [ 42.799430] ? down_read_trylock+0xdb/0x170 [ 42.804081] syscall_return_slowpath+0x3a7/0x450 [ 42.808802] ? prepare_exit_to_usermode+0x220/0x220 [ 42.813786] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 42.818700] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.823683] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.828410] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 42.833131] RIP: 0033:0x445469 [ 42.836286] RSP: 002b:00007fc04af4bdb8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 42.843960] RAX: 0000000000000006 RBX: 0000000000000000 RCX: 0000000000445469 [ 42.851197] RDX: 0000000000000006 RSI: 0000000020aa7000 RDI: 0000000000000003 [ 42.858445] RBP: 0000000000000000 R08: 0000000020aa7000 R09: 000000000000001c [ 42.865681] R10: 0000000000008000 R11: 0000000000000212 R12: 0000000000000000 [ 42.872926] R13: 00007ffc987bb64f R14: 00007fc04af4c9c0 R15: 0000000000000000 [ 42.880750] Dumping ftrace buffer: [ 42.884326] (ftrace buffer empty) [ 42.888003] Kernel Offset: disabled [ 42.891600] Rebooting in 86400 seconds..