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-net-kasan-gce-5,10.128.0.6' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 46.981520] refcount_t: underflow; use-after-free. [ 46.982372] ------------[ cut here ]------------ [ 46.983214] WARNING: CPU: 0 PID: 3010 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 46.984381] Kernel panic - not syncing: panic_on_warn set ... [ 46.984381] [ 46.985355] CPU: 0 PID: 3010 Comm: syzkaller806187 Not tainted 4.13.0-rc4+ #5 [ 46.986306] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 46.987573] Call Trace: [ 46.987932] dump_stack+0x194/0x257 [ 46.988444] ? arch_local_irq_restore+0x53/0x53 [ 46.989080] panic+0x1e4/0x417 [ 46.989513] ? __warn+0x1d9/0x1d9 [ 46.989977] ? show_regs_print_info+0x65/0x65 [ 46.990589] ? refcount_sub_and_test+0x167/0x1b0 [ 46.991232] __warn+0x1c4/0x1d9 [ 46.991674] ? refcount_sub_and_test+0x167/0x1b0 [ 46.992306] report_bug+0x211/0x2d0 [ 46.992798] fixup_bug+0x40/0x90 [ 46.993253] do_trap+0x260/0x390 [ 46.993712] do_error_trap+0x120/0x390 [ 46.994237] ? do_trap+0x390/0x390 [ 46.994713] ? refcount_sub_and_test+0x167/0x1b0 [ 46.995343] ? vprintk_emit+0x3ea/0x590 [ 46.995884] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 46.996533] do_invalid_op+0x1b/0x20 [ 46.997032] invalid_op+0x1e/0x30 [ 46.997507] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 46.998222] RSP: 0018:ffff8801d23ee330 EFLAGS: 00010286 [ 46.998931] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 46.999891] RDX: 0000000000000026 RSI: 1ffff1003a47dc26 RDI: ffffed003a47dc5a [ 47.000841] RBP: ffff8801d23ee3c0 R08: 0000000000000001 R09: 0000000000000000 [ 47.002810] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a47dc67 [ 47.010048] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d00e99fc [ 47.017305] ? refcount_inc+0x50/0x50 [ 47.021073] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 47.025794] ? sctp_association_free+0x2d0/0x930 [ 47.030511] ? sctp_do_sm+0x28e7/0x6d90 [ 47.034453] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 47.039169] ? sctp_close+0x3c6/0x980 [ 47.042933] ? inet_release+0xed/0x1c0 [ 47.046788] sctp_wfree+0x183/0x620 [ 47.050385] ? __sctp_write_space+0x910/0x910 [ 47.054848] skb_release_head_state+0x124/0x200 [ 47.059488] skb_release_all+0x15/0x60 [ 47.063338] consume_skb+0x153/0x490 [ 47.067016] ? sctp_chunk_put+0x99/0x420 [ 47.071046] ? alloc_skb_with_frags+0x710/0x710 [ 47.075684] ? sctp_chunk_hold+0x20/0x20 [ 47.079713] ? refcount_sub_and_test+0x115/0x1b0 [ 47.084431] ? refcount_inc+0x50/0x50 [ 47.088196] ? mark_held_locks+0xaf/0x100 [ 47.092312] ? sctp_datamsg_put+0x456/0x560 [ 47.096605] sctp_chunk_put+0x29c/0x420 [ 47.100546] ? sctp_chunk_hold+0x20/0x20 [ 47.104576] ? sctp_transport_dst_confirm+0x50/0x50 [ 47.109561] ? noop_count+0x40/0x40 [ 47.113168] sctp_chunk_free+0x53/0x60 [ 47.117027] __sctp_outq_teardown+0xc7d/0x15a0 [ 47.121580] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 47.126481] ? lock_downgrade+0x990/0x990 [ 47.130596] ? lock_release+0xa40/0xa40 [ 47.134538] ? __free_insn_slot+0x5c0/0x5c0 [ 47.138826] ? update_stack_state+0x700/0x700 [ 47.143285] ? print_usage_bug+0x480/0x480 [ 47.147493] ? is_bpf_text_address+0xa4/0x120 [ 47.151953] ? __kernel_text_address+0xae/0xe0 [ 47.156498] ? unwind_get_return_address+0x61/0xa0 [ 47.161391] ? __save_stack_trace+0x7e/0xd0 [ 47.165687] ? check_noncircular+0x20/0x20 [ 47.169886] ? print_usage_bug+0x480/0x480 [ 47.174082] ? SOFTIRQ_verbose+0x10/0x10 [ 47.178104] ? save_stack_trace+0x16/0x20 [ 47.182214] ? save_trace+0x11f/0x350 [ 47.185984] ? lock_acquire+0x1d5/0x580 [ 47.189921] ? lock_acquire+0x1d5/0x580 [ 47.193859] ? lock_timer_base+0x1a3/0x2b0 [ 47.198067] ? find_held_lock+0x35/0x1d0 [ 47.202101] ? sock_def_wakeup+0x1f9/0x350 [ 47.206297] ? lock_downgrade+0x990/0x990 [ 47.210408] ? lock_release+0xa40/0xa40 [ 47.214351] sctp_outq_free+0x15/0x20 [ 47.218120] sctp_association_free+0x2d0/0x930 [ 47.222676] ? sctp_asconf_queue_teardown+0x700/0x700 [ 47.227837] ? sock_def_wakeup+0x222/0x350 [ 47.232037] ? sk_dst_check+0x560/0x560 [ 47.235983] ? sctp_association_put+0x74/0x2f0 [ 47.240530] ? sctp_association_hold+0x20/0x20 [ 47.245083] ? print_usage_bug+0x480/0x480 [ 47.249279] ? find_held_lock+0x35/0x1d0 [ 47.253301] ? sctp_sm_lookup_event+0x95/0x3c0 [ 47.257850] sctp_do_sm+0x28e7/0x6d90 [ 47.261626] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 47.267651] ? print_usage_bug+0x480/0x480 [ 47.271853] ? print_usage_bug+0x480/0x480 [ 47.276069] ? find_held_lock+0x35/0x1d0 [ 47.280099] ? skb_dequeue+0x12a/0x180 [ 47.284059] ? lock_downgrade+0x990/0x990 [ 47.288178] ? do_raw_spin_trylock+0x190/0x190 [ 47.292726] ? mark_held_locks+0xaf/0x100 [ 47.296844] ? trace_hardirqs_on+0xd/0x10 [ 47.300963] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 47.305511] sctp_close+0x3c6/0x980 [ 47.309109] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 47.314349] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 47.319329] ? trace_hardirqs_on+0xd/0x10 [ 47.323449] ? rcu_idle_enter+0x1a0/0x1a0 [ 47.327563] ? locks_remove_file+0x414/0x560 [ 47.331936] ? fcntl_setlk+0x10c0/0x10c0 [ 47.335958] ? find_held_lock+0x35/0x1d0 [ 47.339985] ? __fsnotify_parent+0xb4/0x3a0 [ 47.344268] ? ip_mc_drop_socket+0x1ce/0x230 [ 47.348643] inet_release+0xed/0x1c0 [ 47.352324] sock_release+0x8d/0x1e0 [ 47.356004] ? sock_release+0x1e0/0x1e0 [ 47.359939] sock_close+0x16/0x20 [ 47.363356] __fput+0x327/0x7e0 [ 47.366605] ? fput+0x140/0x140 [ 47.369856] ? check_same_owner+0x320/0x320 [ 47.374151] ____fput+0x15/0x20 [ 47.377394] task_work_run+0x18a/0x260 [ 47.381248] ? task_work_cancel+0x210/0x210 [ 47.385531] ? free_nsproxy+0x185/0x1f0 [ 47.389467] ? switch_task_namespaces+0xa2/0xc0 [ 47.394104] do_exit+0xa3a/0x1b10 [ 47.397521] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 47.402682] ? mm_update_next_owner+0x930/0x930 [ 47.407314] ? lock_release+0xa40/0xa40 [ 47.411252] ? __lru_cache_add+0x2a4/0x410 [ 47.415450] ? __pagevec_lru_add+0x30/0x30 [ 47.419659] ? get_mem_cgroup_from_mm+0x49b/0x710 [ 47.424471] ? __lock_acquire+0x6ef/0x3dc0 [ 47.428666] ? check_noncircular+0x20/0x20 [ 47.432864] ? lru_cache_add+0x1c7/0x3a0 [ 47.436892] ? unlock_page_memcg+0x130/0x130 [ 47.441263] ? lru_cache_add_file+0x20/0x20 [ 47.445549] ? __mem_cgroup_threshold+0x8f0/0x8f0 [ 47.450356] ? check_noncircular+0x20/0x20 [ 47.454564] ? find_held_lock+0x35/0x1d0 [ 47.458600] ? find_held_lock+0x35/0x1d0 [ 47.462642] ? get_signal+0x855/0x17e0 [ 47.466493] ? lock_downgrade+0x990/0x990 [ 47.470612] do_group_exit+0x149/0x400 [ 47.474463] ? __lock_is_held+0xb6/0x140 [ 47.478485] ? SyS_exit+0x30/0x30 [ 47.481914] ? _raw_spin_unlock_irq+0x27/0x70 [ 47.486393] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 47.491379] get_signal+0x7e8/0x17e0 [ 47.495083] ? ptrace_notify+0x130/0x130 [ 47.499111] ? __fd_install+0x2da/0x6a0 [ 47.503051] ? lock_downgrade+0x990/0x990 [ 47.507173] ? __lock_is_held+0xb6/0x140 [ 47.511211] do_signal+0x94/0x1ee0 [ 47.514715] ? __fd_install+0x2f7/0x6a0 [ 47.518653] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.523375] ? get_unused_fd_flags+0x190/0x190 [ 47.527921] ? setup_sigcontext+0x7d0/0x7d0 [ 47.532216] ? copy_user_generic_unrolled+0x89/0xc0 [ 47.537200] ? _copy_to_user+0xa2/0xc0 [ 47.541061] ? fd_install+0x4d/0x60 [ 47.544649] ? fput+0xd2/0x140 [ 47.547807] ? SYSC_accept4+0x4ec/0x850 [ 47.551744] ? exit_to_usermode_loop+0x98/0x300 [ 47.556381] exit_to_usermode_loop+0x224/0x300 [ 47.560929] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 47.566431] ? handle_mm_fault+0x4e3/0x940 [ 47.570637] syscall_return_slowpath+0x3a7/0x450 [ 47.575356] ? prepare_exit_to_usermode+0x220/0x220 [ 47.580340] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 47.585232] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 47.590216] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 47.594941] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 47.599658] RIP: 0033:0x445e49 [ 47.602810] RSP: 002b:00007f70e45f0dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 47.610480] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000445e49 [ 47.617711] RDX: 000000002048bffc RSI: 0000000020b4afe4 RDI: 0000000000000003 [ 47.624946] RBP: 0000000000000000 R08: 00007f70e45f1700 R09: 00007f70e45f1700 [ 47.632180] R10: 00007f70e45f1700 R11: 0000000000000202 R12: 0000000000000000 [ 47.639413] R13: 00000000007efe6f R14: 00007f70e45f19c0 R15: 0000000000000000 [ 47.647175] Dumping ftrace buffer: [ 47.650719] (ftrace buffer empty) [ 47.654398] Kernel Offset: disabled [ 47.657991] Rebooting in 86400 seconds..