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-mmots-kasan-gce-5,10.128.15.240' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 23.286122] refcount_t: underflow; use-after-free. [ 23.291234] ------------[ cut here ]------------ [ 23.296204] WARNING: CPU: 1 PID: 2985 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 23.304887] Kernel panic - not syncing: panic_on_warn set ... [ 23.304887] [ 23.312224] CPU: 1 PID: 2985 Comm: syzkaller315324 Not tainted 4.14.0-rc2-mm1+ #9 [ 23.319811] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 23.329138] Call Trace: [ 23.331702] dump_stack+0x194/0x257 [ 23.335303] ? arch_local_irq_restore+0x53/0x53 [ 23.339954] panic+0x1e4/0x417 [ 23.343116] ? __warn+0x1d9/0x1d9 [ 23.346538] ? show_regs_print_info+0x65/0x65 [ 23.351019] ? refcount_sub_and_test+0x167/0x1b0 [ 23.355744] __warn+0x1c4/0x1d9 [ 23.358996] ? refcount_sub_and_test+0x167/0x1b0 [ 23.363729] report_bug+0x211/0x2d0 [ 23.367332] fixup_bug+0x40/0x90 [ 23.370674] do_trap+0x260/0x390 [ 23.374018] do_error_trap+0x120/0x390 [ 23.377880] ? do_trap+0x390/0x390 [ 23.381391] ? refcount_sub_and_test+0x167/0x1b0 [ 23.386118] ? vprintk_emit+0x3ea/0x590 [ 23.390073] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 23.394898] do_invalid_op+0x1b/0x20 [ 23.398586] invalid_op+0x18/0x20 [ 23.402010] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 23.407343] RSP: 0018:ffff8801cdc26420 EFLAGS: 00010286 [ 23.412681] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 23.419921] RDX: 0000000000000026 RSI: 1ffff10039b84c44 RDI: ffffed0039b84c78 [ 23.427162] RBP: ffff8801cdc264b0 R08: ffff8801cdc25b10 R09: 0000000000000000 [ 23.434407] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039b84c85 [ 23.441647] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce2a5364 [ 23.448915] ? refcount_inc+0x50/0x50 [ 23.452688] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 23.457424] ? sctp_association_free+0x2d0/0x930 [ 23.462148] ? sctp_do_sm+0x28e7/0x6dd0 [ 23.466092] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 23.470817] ? sctp_close+0x3c6/0x980 [ 23.474588] ? inet_release+0xed/0x1c0 [ 23.478452] sctp_wfree+0x183/0x620 [ 23.482049] ? __sctp_write_space+0x910/0x910 [ 23.486517] skb_release_head_state+0x124/0x200 [ 23.491161] skb_release_all+0x15/0x60 [ 23.495014] consume_skb+0x153/0x490 [ 23.498695] ? sctp_chunk_put+0x99/0x420 [ 23.502725] ? alloc_skb_with_frags+0x710/0x710 [ 23.507365] ? sctp_chunk_hold+0x20/0x20 [ 23.511399] ? refcount_sub_and_test+0x115/0x1b0 [ 23.516124] ? refcount_inc+0x50/0x50 [ 23.519895] ? mark_held_locks+0xb2/0x100 [ 23.524015] ? sctp_datamsg_put+0x456/0x560 [ 23.528314] sctp_chunk_put+0x29c/0x420 [ 23.532261] ? sctp_chunk_hold+0x20/0x20 [ 23.536295] ? sctp_transport_dst_confirm+0x50/0x50 [ 23.541298] sctp_chunk_free+0x53/0x60 [ 23.545155] __sctp_outq_teardown+0xc7d/0x15a0 [ 23.549711] ? inet6_release+0x50/0x70 [ 23.553576] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 23.558475] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 23.563464] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 23.568449] ? unwind_dump+0x4c0/0x4c0 [ 23.572310] ? unwind_dump+0x4c0/0x4c0 [ 23.576170] ? copy_trace+0x1d0/0x1d0 [ 23.579945] ? check_noncircular+0x20/0x20 [ 23.584150] ? check_noncircular+0x20/0x20 [ 23.588351] ? unwind_get_return_address+0x61/0xa0 [ 23.593253] ? __save_stack_trace+0x61/0xd0 [ 23.597548] ? check_noncircular+0x20/0x20 [ 23.601755] ? print_usage_bug+0x480/0x480 [ 23.605967] ? find_held_lock+0x39/0x1d0 [ 23.610007] ? lock_downgrade+0x990/0x990 [ 23.614132] ? sk_dst_check+0x560/0x560 [ 23.618078] ? rcu_read_lock_sched_held+0x108/0x120 [ 23.623065] ? lock_release+0xd70/0xd70 [ 23.627013] sctp_outq_free+0x15/0x20 [ 23.630783] sctp_association_free+0x2d0/0x930 [ 23.635338] ? sctp_asconf_queue_teardown+0x700/0x700 [ 23.640499] ? sock_def_wakeup+0x222/0x350 [ 23.644704] ? sk_dst_check+0x560/0x560 [ 23.648655] ? sctp_association_put+0x74/0x2f0 [ 23.653206] ? sctp_association_hold+0x20/0x20 [ 23.657757] ? unwind_dump+0x4c0/0x4c0 [ 23.661622] sctp_do_sm+0x28e7/0x6dd0 [ 23.665409] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 23.671440] ? print_usage_bug+0x480/0x480 [ 23.675646] ? __lock_acquire+0x20fd/0x4620 [ 23.679939] ? print_usage_bug+0x480/0x480 [ 23.684145] ? find_held_lock+0x39/0x1d0 [ 23.688186] ? lock_downgrade+0x990/0x990 [ 23.692309] ? skb_dequeue+0x22/0x180 [ 23.696085] ? do_raw_spin_trylock+0x190/0x190 [ 23.700644] ? mark_held_locks+0xb2/0x100 [ 23.704770] ? trace_hardirqs_on+0xd/0x10 [ 23.708894] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 23.713449] sctp_close+0x3c6/0x980 [ 23.717055] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 23.722304] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 23.727036] ? retint_kernel+0x10/0x10 [ 23.730899] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 23.735367] ? ipv6_sock_mc_close+0x148/0x1a0 [ 23.739834] ? ip_mc_drop_socket+0x1ce/0x230 [ 23.744212] ? __fsnotify_parent+0xb4/0x3a0 [ 23.748505] inet_release+0xed/0x1c0 [ 23.752191] inet6_release+0x50/0x70 [ 23.755873] sock_release+0x8d/0x1e0 [ 23.759566] ? sock_release+0x1e0/0x1e0 [ 23.763507] sock_close+0x16/0x20 [ 23.766930] __fput+0x333/0x7f0 [ 23.770185] ? fput+0x140/0x140 [ 23.773435] ? _raw_spin_unlock_irq+0x27/0x70 [ 23.777910] ____fput+0x15/0x20 [ 23.781159] task_work_run+0x199/0x270 [ 23.785019] ? task_work_cancel+0x210/0x210 [ 23.789308] ? _raw_spin_unlock+0x22/0x30 [ 23.793426] ? switch_task_namespaces+0x87/0xc0 [ 23.798070] do_exit+0x9c8/0x1b00 [ 23.801492] ? lock_downgrade+0x990/0x990 [ 23.805614] ? mm_update_next_owner+0x930/0x930 [ 23.810257] ? release_sock+0x74/0x2a0 [ 23.814121] ? do_raw_spin_trylock+0x190/0x190 [ 23.818675] ? trace_hardirqs_on+0xd/0x10 [ 23.822790] ? __local_bh_enable_ip+0x9d/0x160 [ 23.827352] ? __local_bh_enable_ip+0x9d/0x160 [ 23.831911] ? release_sock+0x1d4/0x2a0 [ 23.835855] ? trace_hardirqs_on+0xd/0x10 [ 23.839971] ? __local_bh_enable_ip+0x9d/0x160 [ 23.844523] ? check_noncircular+0x20/0x20 [ 23.848724] ? release_sock+0x1d4/0x2a0 [ 23.852671] ? sctp_shutdown+0x2d0/0x2d0 [ 23.856703] ? __release_sock+0x360/0x360 [ 23.860825] ? sctp_primitive_SEND+0xa0/0xd0 [ 23.865208] ? sctp_sendmsg+0x570/0x3200 [ 23.869243] ? find_held_lock+0x39/0x1d0 [ 23.873282] ? lock_downgrade+0x990/0x990 [ 23.877398] ? recalc_sigpending_tsk+0x117/0x150 [ 23.882123] ? recalc_sigpending+0x103/0x160 [ 23.886501] ? recalc_sigpending_tsk+0x150/0x150 [ 23.891485] ? get_signal+0x2b2/0x16d0 [ 23.895354] do_group_exit+0x149/0x400 [ 23.899210] ? __lock_is_held+0xbc/0x140 [ 23.903239] ? SyS_exit+0x30/0x30 [ 23.906662] ? _raw_spin_unlock_irq+0x27/0x70 [ 23.911127] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 23.916117] get_signal+0x73f/0x16d0 [ 23.919810] ? ptrace_notify+0x130/0x130 [ 23.923842] ? inet_sendmsg+0x11f/0x5e0 [ 23.927786] ? inet_sendmsg+0x126/0x5e0 [ 23.931733] ? rcu_pm_notify+0xc0/0xc0 [ 23.935589] ? inet_recvmsg+0x5f0/0x5f0 [ 23.939541] ? ___sys_sendmsg+0x4a0/0x8a0 [ 23.943658] ? rcu_read_lock_sched_held+0x108/0x120 [ 23.948646] ? kfree+0x1e7/0x250 [ 23.951982] ? ___sys_sendmsg+0x4a5/0x8a0 [ 23.956106] do_signal+0x94/0x1ee0 [ 23.959620] ? wake_up_q+0x8a/0xe0 [ 23.963138] ? setup_sigcontext+0x7d0/0x7d0 [ 23.967453] ? call_rwsem_wake+0x1b/0x30 [ 23.971490] ? exit_to_usermode_loop+0x8c/0x310 [ 23.976133] exit_to_usermode_loop+0x214/0x310 [ 23.980685] ? __sys_sendmsg+0x13b/0x210 [ 23.984719] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 23.990228] ? __do_page_fault+0xb60/0xb60 [ 23.994639] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 23.999632] syscall_return_slowpath+0x42f/0x510 [ 24.004355] ? finish_task_switch+0x1f6/0x740 [ 24.008823] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 24.013812] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 24.018714] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 24.023699] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 24.028429] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 24.033153] RIP: 0033:0x445609 [ 24.036312] RSP: 002b:00007f13dbc24dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e [ 24.043991] RAX: 000000000000000e RBX: 0000000000000000 RCX: 0000000000445609 [ 24.051228] RDX: 0000000000040000 RSI: 0000000020ee7000 RDI: 0000000000000003 [ 24.058466] RBP: 0000000000000000 R08: 00007f13dbc25700 R09: 00007f13dbc25700 [ 24.065704] R10: 00007f13dbc25700 R11: 0000000000000202 R12: 0000000000000000 [ 24.072942] R13: 00007ffdfaeda15f R14: 00007f13dbc259c0 R15: 0000000000000000 [ 24.080391] Dumping ftrace buffer: [ 24.083946] (ftrace buffer empty) [ 24.087632] Kernel Offset: disabled [ 24.091238] Rebooting in 86400 seconds..