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-1,10.128.0.33' (ECDSA) to the list of known hosts. net.ipv6.conf.syz0.accept_dad = 0 net.ipv6.conf.syz0.router_solicitations = 0 executing program syzkaller login: [ 59.562164] refcount_t: underflow; use-after-free. [ 59.567213] ------------[ cut here ]------------ [ 59.572145] WARNING: CPU: 0 PID: 3008 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 59.580821] Kernel panic - not syncing: panic_on_warn set ... [ 59.580821] [ 59.588158] CPU: 0 PID: 3008 Comm: syzkaller717923 Not tainted 4.14.0-rc3+ #117 [ 59.595575] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 59.604898] Call Trace: [ 59.607460] dump_stack+0x194/0x257 [ 59.611061] ? arch_local_irq_restore+0x53/0x53 [ 59.615714] panic+0x1e4/0x417 [ 59.618879] ? __warn+0x1d9/0x1d9 [ 59.622300] ? show_regs_print_info+0x65/0x65 [ 59.626784] ? refcount_sub_and_test+0x167/0x1b0 [ 59.631515] __warn+0x1c4/0x1d9 [ 59.634768] ? refcount_sub_and_test+0x167/0x1b0 [ 59.639502] report_bug+0x211/0x2d0 [ 59.643113] fixup_bug+0x40/0x90 [ 59.646451] do_trap+0x260/0x390 [ 59.649798] do_error_trap+0x120/0x390 [ 59.653662] ? do_trap+0x390/0x390 [ 59.657175] ? refcount_sub_and_test+0x167/0x1b0 [ 59.661900] ? vprintk_emit+0x3ea/0x590 [ 59.665856] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 59.670676] do_invalid_op+0x1b/0x20 [ 59.674359] invalid_op+0x18/0x20 [ 59.677786] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 59.683117] RSP: 0018:ffff8801cfede440 EFLAGS: 00010282 [ 59.688461] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 59.695709] RDX: 0000000000000026 RSI: 1ffff10039fdbc48 RDI: ffffed0039fdbc7c [ 59.702950] RBP: ffff8801cfede4d0 R08: ffff8801cfeddb30 R09: 0000000000000000 [ 59.710189] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039fdbc89 [ 59.717438] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801dadda264 [ 59.724707] ? refcount_inc+0x50/0x50 [ 59.728480] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 59.733205] ? sctp_association_free+0x2d0/0x930 [ 59.737931] ? sctp_do_sm+0x28e7/0x6dd0 [ 59.741874] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 59.746598] ? sctp_close+0x3c6/0x980 [ 59.750367] ? inet_release+0xed/0x1c0 [ 59.754231] sctp_wfree+0x183/0x620 [ 59.757828] ? __sctp_write_space+0x910/0x910 [ 59.762303] skb_release_head_state+0x124/0x200 [ 59.766944] skb_release_all+0x15/0x60 [ 59.770801] consume_skb+0x153/0x490 [ 59.774485] ? sctp_chunk_put+0x99/0x420 [ 59.778520] ? alloc_skb_with_frags+0x710/0x710 [ 59.783164] ? sctp_chunk_hold+0x20/0x20 [ 59.787203] ? refcount_sub_and_test+0x115/0x1b0 [ 59.791932] ? refcount_inc+0x50/0x50 [ 59.795708] ? mark_held_locks+0xb2/0x100 [ 59.799831] ? sctp_datamsg_put+0x456/0x560 [ 59.804137] sctp_chunk_put+0x29c/0x420 [ 59.808088] ? sctp_chunk_hold+0x20/0x20 [ 59.812125] ? sctp_transport_dst_confirm+0x50/0x50 [ 59.817113] ? unwind_dump+0x4c0/0x4c0 [ 59.820973] ? unwind_dump+0x4c0/0x4c0 [ 59.824841] sctp_chunk_free+0x53/0x60 [ 59.828701] __sctp_outq_teardown+0xc7d/0x15a0 [ 59.833256] ? sock_release+0x8d/0x1e0 [ 59.837121] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 59.842021] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 59.847013] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 59.852001] ? unwind_dump+0x4c0/0x4c0 [ 59.855857] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 59.860846] ? unwind_dump+0x4c0/0x4c0 [ 59.864716] ? check_noncircular+0x20/0x20 [ 59.868921] ? check_noncircular+0x20/0x20 [ 59.873126] ? unwind_get_return_address+0x61/0xa0 [ 59.878026] ? __save_stack_trace+0x61/0xd0 [ 59.882322] ? check_noncircular+0x20/0x20 [ 59.886529] ? print_usage_bug+0x480/0x480 [ 59.890740] ? find_held_lock+0x39/0x1d0 [ 59.894783] ? lock_downgrade+0x990/0x990 [ 59.898910] ? sk_dst_check+0x560/0x560 [ 59.902856] ? rcu_read_lock_sched_held+0x108/0x120 [ 59.907849] ? lock_release+0xd70/0xd70 [ 59.911804] sctp_outq_free+0x15/0x20 [ 59.915583] sctp_association_free+0x2d0/0x930 [ 59.920143] ? sctp_asconf_queue_teardown+0x700/0x700 [ 59.925309] ? sock_def_wakeup+0x222/0x350 [ 59.929517] ? sk_dst_check+0x560/0x560 [ 59.933472] ? sctp_association_put+0x74/0x2f0 [ 59.938028] ? sctp_association_hold+0x20/0x20 [ 59.942584] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 59.947751] ? find_held_lock+0x39/0x1d0 [ 59.954049] sctp_do_sm+0x28e7/0x6dd0 [ 59.957840] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 59.963872] ? print_usage_bug+0x480/0x480 [ 59.968078] ? do_raw_spin_trylock+0x190/0x190 [ 59.972633] ? print_usage_bug+0x480/0x480 [ 59.976845] ? find_held_lock+0x39/0x1d0 [ 59.980889] ? lock_downgrade+0x990/0x990 [ 59.985021] ? skb_dequeue+0x22/0x180 [ 59.988803] ? do_raw_spin_trylock+0x190/0x190 [ 59.993364] ? mark_held_locks+0xb2/0x100 [ 59.997503] ? trace_hardirqs_on+0xd/0x10 [ 60.001628] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 60.006187] sctp_close+0x3c6/0x980 [ 60.009794] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 60.015043] ? dentry_free+0xcd/0x130 [ 60.018830] ? rcu_read_lock_sched_held+0x108/0x120 [ 60.023821] ? kmem_cache_free+0x249/0x280 [ 60.028032] ? dentry_free+0xd2/0x130 [ 60.031808] ? locks_remove_file+0x3fa/0x5a0 [ 60.036193] ? fcntl_setlk+0x10d0/0x10d0 [ 60.040231] ? __fsnotify_parent+0xb4/0x3a0 [ 60.044524] ? ip_mc_drop_socket+0x1ce/0x230 [ 60.048910] inet_release+0xed/0x1c0 [ 60.052603] sock_release+0x8d/0x1e0 [ 60.056289] ? sock_release+0x1e0/0x1e0 [ 60.060234] sock_close+0x16/0x20 [ 60.063659] __fput+0x333/0x7f0 [ 60.066921] ? fput+0x140/0x140 [ 60.070174] ? check_same_owner+0x320/0x320 [ 60.074475] ____fput+0x15/0x20 [ 60.077735] task_work_run+0x199/0x270 [ 60.081599] ? task_work_cancel+0x210/0x210 [ 60.085892] ? free_nsproxy+0x185/0x1f0 [ 60.089839] ? switch_task_namespaces+0xa2/0xc0 [ 60.095181] do_exit+0x9d2/0x1af0 [ 60.098612] ? __lock_acquire+0x6d0/0x4620 [ 60.102819] ? mm_update_next_owner+0x930/0x930 [ 60.107460] ? kernel_text_address+0x102/0x140 [ 60.112030] ? __kernel_text_address+0xd/0x40 [ 60.116508] ? unwind_get_return_address+0x61/0xa0 [ 60.121417] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 60.126584] ? save_stack_trace+0x16/0x20 [ 60.130709] ? __lock_acquire+0x20fd/0x4620 [ 60.135004] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 60.140164] ? check_noncircular+0x20/0x20 [ 60.144390] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 60.149560] ? find_held_lock+0x39/0x1d0 [ 60.153614] ? lock_downgrade+0x990/0x990 [ 60.157735] ? recalc_sigpending_tsk+0x117/0x150 [ 60.162467] ? recalc_sigpending+0x103/0x160 [ 60.166845] ? recalc_sigpending_tsk+0x150/0x150 [ 60.171568] ? get_signal+0x2b2/0x16d0 [ 60.175438] do_group_exit+0x149/0x400 [ 60.179296] ? __lock_is_held+0xbc/0x140 [ 60.183325] ? SyS_exit+0x30/0x30 [ 60.186748] ? _raw_spin_unlock_irq+0x27/0x70 [ 60.191215] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 60.196206] get_signal+0x73f/0x16d0 [ 60.199901] ? ptrace_notify+0x130/0x130 [ 60.203937] ? get_unused_fd_flags+0x190/0x190 [ 60.208503] ? __lock_is_held+0xbc/0x140 [ 60.212547] do_signal+0x94/0x1ee0 [ 60.216074] ? __fd_install+0x2f7/0x6a0 [ 60.220038] ? __might_fault+0xe0/0x1d0 [ 60.223994] ? get_unused_fd_flags+0x190/0x190 [ 60.228556] ? setup_sigcontext+0x7d0/0x7d0 [ 60.232858] ? __might_sleep+0x95/0x190 [ 60.236808] ? __might_fault+0x188/0x1d0 [ 60.240846] ? fput+0xd2/0x140 [ 60.244013] ? SYSC_accept4+0x4f2/0x850 [ 60.247961] ? exit_to_usermode_loop+0x8c/0x310 [ 60.252609] exit_to_usermode_loop+0x214/0x310 [ 60.257180] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 60.262689] ? _raw_spin_unlock_irq+0x27/0x70 [ 60.267159] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 60.272157] syscall_return_slowpath+0x42f/0x510 [ 60.276881] ? finish_task_switch+0x1aa/0x740 [ 60.281348] ? prepare_exit_to_usermode+0x2d0/0x2d0 [ 60.286337] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 60.291240] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 60.296228] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 60.300961] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 60.305687] RIP: 0033:0x44aea9 [ 60.308848] RSP: 002b:00007f3053622d08 EFLAGS: 00000246 ORIG_RAX: 0000000000000120 [ 60.316528] RAX: 0000000000000005 RBX: 0000000000000000 RCX: 000000000044aea9 [ 60.323769] RDX: 0000000020146ffc RSI: 0000000020000000 RDI: 0000000000000004 [ 60.331007] RBP: 0000000000000000 R08: 00007f3053623700 R09: 00007f3053623700 [ 60.338247] R10: 0000000000000800 R11: 0000000000000246 R12: 0000000000000000 [ 60.345490] R13: 00000000007efdaf R14: 00007f30536239c0 R15: 0000000000000000 [ 60.353326] Dumping ftrace buffer: [ 60.356896] (ftrace buffer empty) [ 60.360582] Kernel Offset: disabled [ 60.364189] Rebooting in 86400 seconds..