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-4,10.128.0.20' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 51.163913] refcount_t: underflow; use-after-free. [ 51.168954] ------------[ cut here ]------------ [ 51.173877] WARNING: CPU: 1 PID: 3010 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 51.182545] Kernel panic - not syncing: panic_on_warn set ... [ 51.182545] [ 51.189879] CPU: 1 PID: 3010 Comm: syzkaller053685 Not tainted 4.13.0-next-20170905+ #15 [ 51.198072] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.207394] Call Trace: [ 51.209953] dump_stack+0x194/0x257 [ 51.213552] ? arch_local_irq_restore+0x53/0x53 [ 51.218204] panic+0x1e4/0x417 [ 51.221378] ? __warn+0x1d9/0x1d9 [ 51.224811] ? show_regs_print_info+0x65/0x65 [ 51.229295] ? refcount_sub_and_test+0x167/0x1b0 [ 51.234020] __warn+0x1c4/0x1d9 [ 51.237267] ? refcount_sub_and_test+0x167/0x1b0 [ 51.241995] report_bug+0x211/0x2d0 [ 51.245598] fixup_bug+0x40/0x90 [ 51.248935] do_trap+0x260/0x390 [ 51.252282] do_error_trap+0x120/0x390 [ 51.256142] ? do_trap+0x390/0x390 [ 51.259664] ? refcount_sub_and_test+0x167/0x1b0 [ 51.264395] ? vprintk_emit+0x3ea/0x590 [ 51.268347] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 51.273163] do_invalid_op+0x1b/0x20 [ 51.276847] invalid_op+0x18/0x20 [ 51.280280] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 51.285611] RSP: 0018:ffff8801ce05e320 EFLAGS: 00010286 [ 51.290947] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 51.298193] RDX: 0000000000000026 RSI: 1ffff10039c0bc24 RDI: ffffed0039c0bc58 [ 51.305432] RBP: ffff8801ce05e3b0 R08: ffff8801ce05da10 R09: 0000000000000000 [ 51.312670] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039c0bc65 [ 51.319910] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce5f92a4 [ 51.327178] ? refcount_inc+0x50/0x50 [ 51.330948] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 51.335671] ? sctp_association_free+0x2d0/0x930 [ 51.340396] ? sctp_do_sm+0x28e7/0x6dd0 [ 51.344339] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 51.349064] ? sctp_close+0x3c6/0x980 [ 51.352853] ? inet_release+0xed/0x1c0 [ 51.356716] sctp_wfree+0x183/0x620 [ 51.360314] ? __sctp_write_space+0x910/0x910 [ 51.364781] skb_release_head_state+0x124/0x200 [ 51.369421] skb_release_all+0x15/0x60 [ 51.373289] consume_skb+0x153/0x490 [ 51.376970] ? sctp_chunk_put+0x99/0x420 [ 51.381004] ? alloc_skb_with_frags+0x710/0x710 [ 51.385642] ? sctp_chunk_hold+0x20/0x20 [ 51.389675] ? refcount_sub_and_test+0x115/0x1b0 [ 51.394405] ? refcount_inc+0x50/0x50 [ 51.398176] ? mark_held_locks+0xb2/0x100 [ 51.402298] ? sctp_datamsg_put+0x456/0x560 [ 51.406600] sctp_chunk_put+0x29c/0x420 [ 51.410552] ? sctp_chunk_hold+0x20/0x20 [ 51.414589] ? sctp_transport_dst_confirm+0x50/0x50 [ 51.419594] sctp_chunk_free+0x53/0x60 [ 51.423452] __sctp_outq_teardown+0xc7d/0x15a0 [ 51.428007] ? sock_release+0x8d/0x1e0 [ 51.431873] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 51.436780] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.441769] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.446764] ? unwind_dump+0x4c0/0x4c0 [ 51.450619] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.455612] ? unwind_dump+0x4c0/0x4c0 [ 51.459491] ? check_noncircular+0x20/0x20 [ 51.463705] ? check_noncircular+0x20/0x20 [ 51.467913] ? unwind_get_return_address+0x61/0xa0 [ 51.472813] ? __save_stack_trace+0x61/0xd0 [ 51.477108] ? check_noncircular+0x20/0x20 [ 51.481318] ? print_usage_bug+0x480/0x480 [ 51.485533] ? find_held_lock+0x39/0x1d0 [ 51.489576] ? lock_downgrade+0x990/0x990 [ 51.493716] ? sk_dst_check+0x560/0x560 [ 51.497664] ? rcu_read_lock_sched_held+0x108/0x120 [ 51.502656] ? lock_release+0xd70/0xd70 [ 51.506608] sctp_outq_free+0x15/0x20 [ 51.510379] sctp_association_free+0x2d0/0x930 [ 51.514938] ? sctp_asconf_queue_teardown+0x700/0x700 [ 51.520100] ? sock_def_wakeup+0x222/0x350 [ 51.524306] ? sk_dst_check+0x560/0x560 [ 51.528254] ? sctp_association_put+0x74/0x2f0 [ 51.532808] ? sctp_association_hold+0x20/0x20 [ 51.537362] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 51.542525] ? lock_downgrade+0x990/0x990 [ 51.546641] ? sctp_sm_lookup_event+0x95/0x3c0 [ 51.551195] sctp_do_sm+0x28e7/0x6dd0 [ 51.554978] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 51.561018] ? __free_insn_slot+0x5c0/0x5c0 [ 51.565316] ? print_usage_bug+0x480/0x480 [ 51.569525] ? print_usage_bug+0x480/0x480 [ 51.573731] ? find_held_lock+0x39/0x1d0 [ 51.577771] ? lock_downgrade+0x990/0x990 [ 51.581899] ? skb_dequeue+0x22/0x180 [ 51.585678] ? do_raw_spin_trylock+0x190/0x190 [ 51.590239] ? mark_held_locks+0xb2/0x100 [ 51.594367] ? trace_hardirqs_on+0xd/0x10 [ 51.598492] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 51.603049] sctp_close+0x3c6/0x980 [ 51.606659] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 51.611905] ? dentry_free+0xcd/0x130 [ 51.615676] ? rcu_read_lock_sched_held+0x108/0x120 [ 51.620665] ? kmem_cache_free+0x249/0x280 [ 51.624874] ? dentry_free+0xd2/0x130 [ 51.628652] ? locks_remove_file+0x3fa/0x5a0 [ 51.633036] ? fcntl_setlk+0x10d0/0x10d0 [ 51.637070] ? __fsnotify_parent+0xb4/0x3a0 [ 51.641364] ? ip_mc_drop_socket+0x1ce/0x230 [ 51.645748] inet_release+0xed/0x1c0 [ 51.649436] sock_release+0x8d/0x1e0 [ 51.653119] ? sock_release+0x1e0/0x1e0 [ 51.657062] sock_close+0x16/0x20 [ 51.660485] __fput+0x333/0x7f0 [ 51.663742] ? fput+0x140/0x140 [ 51.666991] ? check_same_owner+0x320/0x320 [ 51.671285] ? _raw_spin_unlock_irq+0x27/0x70 [ 51.675757] ____fput+0x15/0x20 [ 51.679007] task_work_run+0x199/0x270 [ 51.682869] ? task_work_cancel+0x210/0x210 [ 51.687164] ? _raw_spin_unlock+0x22/0x30 [ 51.691286] ? switch_task_namespaces+0x87/0xc0 [ 51.695933] do_exit+0xa52/0x1b40 [ 51.699361] ? check_noncircular+0x20/0x20 [ 51.703565] ? lock_page_memcg+0x3b0/0x3b0 [ 51.707777] ? __lock_is_held+0xbc/0x140 [ 51.711812] ? mm_update_next_owner+0x930/0x930 [ 51.716449] ? lru_cache_add+0x1c7/0x3a0 [ 51.720479] ? get_mem_cgroup_from_mm+0x710/0x710 [ 51.725293] ? lru_cache_add_file+0x20/0x20 [ 51.729594] ? __lock_acquire+0x732/0x4620 [ 51.733803] ? lock_downgrade+0x990/0x990 [ 51.737926] ? check_noncircular+0x20/0x20 [ 51.742130] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 51.747293] ? do_raw_spin_trylock+0x190/0x190 [ 51.751848] ? lockdep_init_map+0x3d/0x70 [ 51.755974] ? find_held_lock+0x39/0x1d0 [ 51.760019] ? lock_downgrade+0x990/0x990 [ 51.764140] ? recalc_sigpending_tsk+0x117/0x150 [ 51.768869] ? recalc_sigpending+0x103/0x160 [ 51.773247] ? recalc_sigpending_tsk+0x150/0x150 [ 51.777968] ? get_signal+0x397/0x17e0 [ 51.781839] do_group_exit+0x149/0x400 [ 51.785698] ? __lock_is_held+0xbc/0x140 [ 51.789743] ? SyS_exit+0x30/0x30 [ 51.793179] ? _raw_spin_unlock_irq+0x27/0x70 [ 51.797644] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.802633] get_signal+0x7e8/0x17e0 [ 51.806348] ? ptrace_notify+0x130/0x130 [ 51.810402] ? get_unused_fd_flags+0x190/0x190 [ 51.814970] ? __lock_is_held+0xbc/0x140 [ 51.819014] do_signal+0x94/0x1ee0 [ 51.822525] ? __fd_install+0x2f7/0x6a0 [ 51.826478] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.831209] ? get_unused_fd_flags+0x190/0x190 [ 51.835761] ? setup_sigcontext+0x7d0/0x7d0 [ 51.840079] ? copy_user_generic_unrolled+0x89/0xc0 [ 51.845070] ? _copy_to_user+0xa2/0xc0 [ 51.848936] ? fd_install+0x4d/0x60 [ 51.852530] ? fput+0xd2/0x140 [ 51.855697] ? SYSC_accept4+0x4f2/0x850 [ 51.859643] ? exit_to_usermode_loop+0x98/0x300 [ 51.864289] exit_to_usermode_loop+0x224/0x300 [ 51.868845] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 51.874353] ? _raw_spin_unlock_irq+0x27/0x70 [ 51.878825] ? __do_page_fault+0xb60/0xb60 [ 51.883031] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.888027] syscall_return_slowpath+0x42f/0x500 [ 51.892757] ? finish_task_switch+0x1aa/0x740 [ 51.897224] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 51.902211] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 51.907116] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.912104] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.916839] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 51.921564] RIP: 0033:0x447429 [ 51.924729] RSP: 002b:00007fa68c02ddc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 51.932409] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000447429 [ 51.939648] RDX: 000000002048bffc RSI: 0000000020b4afe4 RDI: 0000000000000003 [ 51.946888] RBP: 0000000000000000 R08: 00007fa68c02e700 R09: 00007fa68c02e700 [ 51.954138] R10: 00007fa68c02e700 R11: 0000000000000202 R12: 0000000000000000 [ 51.961376] R13: 00000000007efd4f R14: 00007fa68c02e9c0 R15: 0000000000000000 [ 51.968771] Dumping ftrace buffer: [ 51.972324] (ftrace buffer empty) [ 51.976008] Kernel Offset: disabled [ 51.979611] Rebooting in 86400 seconds..