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-9,10.128.0.32' (ECDSA) to the list of known hosts. executing program executing program syzkaller login: [ 42.599787] refcount_t: underflow; use-after-free. [ 42.600770] ------------[ cut here ]------------ [ 42.601620] WARNING: CPU: 1 PID: 3052 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 42.602853] Kernel panic - not syncing: panic_on_warn set ... [ 42.602853] [ 42.603936] CPU: 1 PID: 3052 Comm: syzkaller001797 Not tainted 4.13.0-rc5-next-20170815+ #3 [ 42.605101] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 42.606355] Call Trace: [ 42.606783] dump_stack+0x194/0x257 [ 42.607276] ? arch_local_irq_restore+0x53/0x53 [ 42.607913] panic+0x1e4/0x417 [ 42.608348] ? __warn+0x1d9/0x1d9 [ 42.608814] ? show_regs_print_info+0x65/0x65 [ 42.609468] ? refcount_sub_and_test+0x167/0x1b0 [ 42.610128] __warn+0x1c4/0x1d9 [ 42.610572] ? refcount_sub_and_test+0x167/0x1b0 [ 42.611209] report_bug+0x211/0x2d0 [ 42.611704] fixup_bug+0x40/0x90 [ 42.612170] do_trap+0x260/0x390 [ 42.612633] do_error_trap+0x120/0x390 [ 42.613178] ? do_trap+0x390/0x390 [ 42.613735] ? refcount_sub_and_test+0x167/0x1b0 [ 42.614395] ? vprintk_emit+0x3ea/0x590 [ 42.614936] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 42.615586] do_invalid_op+0x1b/0x20 [ 42.616085] invalid_op+0x1e/0x30 [ 42.616552] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 42.617260] RSP: 0018:ffff8801ce946320 EFLAGS: 00010286 [ 42.617972] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 42.619036] RDX: 0000000000000026 RSI: 1ffff10039d28c24 RDI: ffffed0039d28c58 [ 42.620156] RBP: ffff8801ce9463b0 R08: 0000000000000001 R09: 0000000000000000 [ 42.627405] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039d28c65 [ 42.634653] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801cf193a3c [ 42.641928] ? refcount_inc+0x50/0x50 [ 42.645706] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 42.650429] ? sctp_association_free+0x2d0/0x930 [ 42.655151] ? sctp_do_sm+0x28e7/0x6d90 [ 42.659094] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.663815] ? sctp_close+0x3c6/0x980 [ 42.667590] ? inet_release+0xed/0x1c0 [ 42.671450] sctp_wfree+0x183/0x620 [ 42.675050] ? __sctp_write_space+0x910/0x910 [ 42.679518] skb_release_head_state+0x124/0x200 [ 42.684155] skb_release_all+0x15/0x60 [ 42.688021] consume_skb+0x153/0x490 [ 42.691703] ? sctp_chunk_put+0x99/0x420 [ 42.695735] ? alloc_skb_with_frags+0x710/0x710 [ 42.700373] ? sctp_chunk_hold+0x20/0x20 [ 42.704404] ? refcount_sub_and_test+0x115/0x1b0 [ 42.709137] ? refcount_inc+0x50/0x50 [ 42.712923] ? mark_held_locks+0xaf/0x100 [ 42.717049] ? sctp_datamsg_put+0x456/0x560 [ 42.721344] sctp_chunk_put+0x29c/0x420 [ 42.725374] ? sctp_chunk_hold+0x20/0x20 [ 42.729404] ? sctp_transport_dst_confirm+0x50/0x50 [ 42.734396] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 42.739565] sctp_chunk_free+0x53/0x60 [ 42.743430] __sctp_outq_teardown+0xc7d/0x15a0 [ 42.747978] ? find_held_lock+0x35/0x1d0 [ 42.752011] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 42.756915] ? print_usage_bug+0x480/0x480 [ 42.761127] ? lock_release+0xa40/0xa40 [ 42.765080] ? print_usage_bug+0x480/0x480 [ 42.769280] ? unwind_dump+0x4c0/0x4c0 [ 42.773143] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 42.778301] ? is_bpf_text_address+0xa4/0x120 [ 42.783162] ? __kernel_text_address+0xae/0xe0 [ 42.787733] ? unwind_get_return_address+0x61/0xa0 [ 42.792632] ? __save_stack_trace+0x7e/0xd0 [ 42.796935] ? check_noncircular+0x20/0x20 [ 42.801147] ? print_usage_bug+0x480/0x480 [ 42.805363] ? print_usage_bug+0x480/0x480 [ 42.809844] ? lock_acquire+0x1d5/0x580 [ 42.813799] ? lock_acquire+0x1d5/0x580 [ 42.817744] ? lock_timer_base+0x1a3/0x2b0 [ 42.821957] ? find_held_lock+0x35/0x1d0 [ 42.826019] ? sock_def_wakeup+0x1f9/0x350 [ 42.830238] ? lock_downgrade+0x990/0x990 [ 42.834356] ? lock_release+0xa40/0xa40 [ 42.838303] sctp_outq_free+0x15/0x20 [ 42.842082] sctp_association_free+0x2d0/0x930 [ 42.846635] ? sctp_asconf_queue_teardown+0x700/0x700 [ 42.851795] ? sock_def_wakeup+0x222/0x350 [ 42.855998] ? sk_dst_check+0x560/0x560 [ 42.859943] ? sctp_association_put+0x74/0x2f0 [ 42.864491] ? sctp_association_hold+0x20/0x20 [ 42.869055] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 42.874213] ? find_held_lock+0x35/0x1d0 [ 42.878242] ? sctp_sm_lookup_event+0x95/0x3c0 [ 42.882792] sctp_do_sm+0x28e7/0x6d90 [ 42.886569] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 42.892593] ? __free_insn_slot+0x5c0/0x5c0 [ 42.896909] ? print_usage_bug+0x480/0x480 [ 42.901112] ? lock_downgrade+0x990/0x990 [ 42.905229] ? print_usage_bug+0x480/0x480 [ 42.909433] ? is_bpf_text_address+0xa4/0x120 [ 42.913898] ? __kernel_text_address+0xae/0xe0 [ 42.918449] ? unwind_get_return_address+0x61/0xa0 [ 42.923360] ? __save_stack_trace+0x7e/0xd0 [ 42.927652] ? find_held_lock+0x35/0x1d0 [ 42.931698] ? skb_dequeue+0x12a/0x180 [ 42.935569] ? lock_downgrade+0x990/0x990 [ 42.939687] ? do_raw_spin_trylock+0x190/0x190 [ 42.944240] ? mark_held_locks+0xaf/0x100 [ 42.948380] ? trace_hardirqs_on+0xd/0x10 [ 42.952503] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.957076] sctp_close+0x3c6/0x980 [ 42.960680] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 42.965923] ? dentry_free+0xcd/0x130 [ 42.969691] ? rcu_read_lock_sched_held+0x108/0x120 [ 42.974675] ? kmem_cache_free+0x249/0x280 [ 42.978878] ? dentry_free+0xd2/0x130 [ 42.982657] ? locks_remove_file+0x3fa/0x5a0 [ 42.987033] ? fcntl_setlk+0x10c0/0x10c0 [ 42.991064] ? __fsnotify_parent+0xb4/0x3a0 [ 42.995352] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.999731] inet_release+0xed/0x1c0 [ 43.003417] sock_release+0x8d/0x1e0 [ 43.007097] ? sock_release+0x1e0/0x1e0 [ 43.011035] sock_close+0x16/0x20 [ 43.014456] __fput+0x327/0x7e0 [ 43.017723] ? fput+0x140/0x140 [ 43.020970] ? check_same_owner+0x320/0x320 [ 43.025274] ? _raw_spin_unlock_irq+0x27/0x70 [ 43.029740] ____fput+0x15/0x20 [ 43.032989] task_work_run+0x199/0x270 [ 43.036845] ? task_work_cancel+0x210/0x210 [ 43.041135] ? _raw_spin_unlock+0x22/0x30 [ 43.045251] ? switch_task_namespaces+0x87/0xc0 [ 43.049892] do_exit+0xa52/0x1b30 [ 43.053316] ? get_mem_cgroup_from_mm+0x47c/0x710 [ 43.058133] ? lock_release+0xa40/0xa40 [ 43.062075] ? mm_update_next_owner+0x930/0x930 [ 43.066708] ? mem_cgroup_css_offline+0x510/0x510 [ 43.071518] ? __lock_is_held+0xb6/0x140 [ 43.075549] ? __lru_cache_add+0x2a4/0x410 [ 43.079754] ? __pagevec_lru_add+0x30/0x30 [ 43.083971] ? __lock_acquire+0x6aa/0x3bc0 [ 43.088190] ? lock_page_memcg+0x3b0/0x3b0 [ 43.092393] ? __lock_is_held+0xb6/0x140 [ 43.096431] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 43.101587] ? __mem_cgroup_threshold+0x8f0/0x8f0 [ 43.106404] ? check_noncircular+0x20/0x20 [ 43.110607] ? mark_held_locks+0xaf/0x100 [ 43.114729] ? find_held_lock+0x35/0x1d0 [ 43.118765] ? find_held_lock+0x35/0x1d0 [ 43.122888] ? get_signal+0x855/0x17e0 [ 43.126743] ? lock_downgrade+0x990/0x990 [ 43.130866] do_group_exit+0x149/0x400 [ 43.134721] ? __lock_is_held+0xb6/0x140 [ 43.138749] ? SyS_exit+0x30/0x30 [ 43.142169] ? _raw_spin_unlock_irq+0x27/0x70 [ 43.146636] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.151632] get_signal+0x7e8/0x17e0 [ 43.155338] ? ptrace_notify+0x130/0x130 [ 43.159369] ? __fd_install+0x2da/0x6a0 [ 43.164300] ? lock_downgrade+0x990/0x990 [ 43.168431] ? __lock_is_held+0xb6/0x140 [ 43.172476] do_signal+0x94/0x1ee0 [ 43.176003] ? __fd_install+0x2f7/0x6a0 [ 43.179949] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 43.184693] ? get_unused_fd_flags+0x190/0x190 [ 43.189249] ? setup_sigcontext+0x7d0/0x7d0 [ 43.193557] ? copy_user_generic_unrolled+0x89/0xc0 [ 43.199340] ? _copy_to_user+0xa2/0xc0 [ 43.203203] ? fd_install+0x4d/0x60 [ 43.206802] ? fput+0xd2/0x140 [ 43.209969] ? SYSC_accept4+0x4ec/0x850 [ 43.213911] ? exit_to_usermode_loop+0x98/0x300 [ 43.218553] exit_to_usermode_loop+0x224/0x300 [ 43.223111] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 43.228625] ? handle_mm_fault+0x4e3/0x940 [ 43.232842] syscall_return_slowpath+0x42f/0x500 [ 43.237579] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 43.242589] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 43.247506] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 43.252494] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 43.257238] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 43.261963] RIP: 0033:0x447429 [ 43.265120] RSP: 002b:00007f3680411dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 43.272799] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000447429 [ 43.280037] RDX: 000000002048bffc RSI: 0000000020b4afe4 RDI: 0000000000000003 [ 43.287277] RBP: 0000000000000000 R08: 00007f3680412700 R09: 00007f3680412700 [ 43.294514] R10: 00007f3680412700 R11: 0000000000000202 R12: 0000000000000000 [ 43.301752] R13: 00000000007efd4f R14: 00007f36804129c0 R15: 0000000000000000 [ 43.309540] Dumping ftrace buffer: [ 43.313131] (ftrace buffer empty) [ 43.316811] Kernel Offset: disabled [ 43.320412] Rebooting in 86400 seconds..