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-3,10.128.0.60' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 41.913913] refcount_t: underflow; use-after-free. [ 41.914981] ------------[ cut here ]------------ [ 41.915940] WARNING: CPU: 0 PID: 3005 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 41.917141] Kernel panic - not syncing: panic_on_warn set ... [ 41.917141] [ 41.918255] CPU: 0 PID: 3005 Comm: syzkaller180602 Not tainted 4.13.0-rc6+ #24 [ 41.919220] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 41.920531] Call Trace: [ 41.920893] dump_stack+0x194/0x257 [ 41.921386] ? arch_local_irq_restore+0x53/0x53 [ 41.922046] panic+0x1e4/0x417 [ 41.922554] ? __warn+0x1d9/0x1d9 [ 41.923028] ? show_regs_print_info+0x65/0x65 [ 41.923659] ? refcount_sub_and_test+0x167/0x1b0 [ 41.924291] __warn+0x1c4/0x1d9 [ 41.924734] ? refcount_sub_and_test+0x167/0x1b0 [ 41.925400] report_bug+0x211/0x2d0 [ 41.925895] fixup_bug+0x40/0x90 [ 41.926352] do_trap+0x260/0x390 [ 41.926824] do_error_trap+0x120/0x390 [ 41.927358] ? vprintk_emit+0x49b/0x590 [ 41.927897] ? do_trap+0x390/0x390 [ 41.928437] ? refcount_sub_and_test+0x167/0x1b0 [ 41.929069] ? vprintk_emit+0x3ea/0x590 [ 41.929648] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 41.930317] do_invalid_op+0x1b/0x20 [ 41.930862] invalid_op+0x1e/0x30 [ 41.931325] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 41.932032] RSP: 0018:ffff8801d0746928 EFLAGS: 00010282 [ 41.932742] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 41.933705] RDX: 0000000000000026 RSI: 1ffff1003a0e8ce5 RDI: ffffed003a0e8d19 [ 41.938778] RBP: ffff8801d07469b8 R08: 0000000000000001 R09: 0000000000000000 [ 41.946016] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a0e8d26 [ 41.953254] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d5616a3c [ 41.960514] ? refcount_sub_and_test+0x167/0x1b0 [ 41.965237] ? refcount_inc+0x50/0x50 [ 41.969005] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 41.973728] ? sctp_association_free+0x2d0/0x930 [ 41.978452] ? sctp_do_sm+0x28e7/0x6dd0 [ 41.982396] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 41.987119] ? sctp_close+0x3c6/0x980 [ 41.990896] ? inet_release+0xed/0x1c0 [ 41.994765] sctp_wfree+0x183/0x620 [ 41.998364] ? __sctp_write_space+0x910/0x910 [ 42.002843] skb_release_head_state+0x124/0x200 [ 42.007484] skb_release_all+0x15/0x60 [ 42.011341] consume_skb+0x153/0x490 [ 42.015022] ? sctp_chunk_put+0x99/0x420 [ 42.019064] ? alloc_skb_with_frags+0x710/0x710 [ 42.023710] ? sctp_chunk_hold+0x20/0x20 [ 42.028272] ? refcount_sub_and_test+0x115/0x1b0 [ 42.033007] ? refcount_inc+0x50/0x50 [ 42.036776] ? mark_held_locks+0xaf/0x100 [ 42.040901] ? sctp_datamsg_put+0x456/0x560 [ 42.045202] sctp_chunk_put+0x29c/0x420 [ 42.049156] ? sctp_chunk_hold+0x20/0x20 [ 42.053194] ? sctp_transport_dst_confirm+0x50/0x50 [ 42.058199] sctp_chunk_free+0x53/0x60 [ 42.062056] __sctp_outq_teardown+0xc7d/0x15a0 [ 42.066609] ? bpf_prog_kallsyms_find+0xbd/0x440 [ 42.071342] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 42.076240] ? is_bpf_text_address+0x7b/0x120 [ 42.080712] ? lock_downgrade+0x990/0x990 [ 42.084831] ? lock_release+0xa40/0xa40 [ 42.088777] ? update_stack_state+0x700/0x700 [ 42.093240] ? print_usage_bug+0x480/0x480 [ 42.097451] ? is_bpf_text_address+0xa4/0x120 [ 42.101914] ? __kernel_text_address+0xae/0xe0 [ 42.106466] ? unwind_get_return_address+0x61/0xa0 [ 42.111365] ? __save_stack_trace+0x7e/0xd0 [ 42.115659] ? check_noncircular+0x20/0x20 [ 42.119872] ? print_usage_bug+0x480/0x480 [ 42.124086] ? save_stack_trace+0x16/0x20 [ 42.128203] ? save_trace+0x11f/0x350 [ 42.131974] ? lock_acquire+0x1d5/0x580 [ 42.135916] ? lock_acquire+0x1d5/0x580 [ 42.139863] ? lock_timer_base+0x1a3/0x2b0 [ 42.144069] ? find_held_lock+0x35/0x1d0 [ 42.148109] ? sock_def_wakeup+0x1f9/0x350 [ 42.152312] ? lock_downgrade+0x990/0x990 [ 42.156430] ? lock_release+0xa40/0xa40 [ 42.160380] sctp_outq_free+0x15/0x20 [ 42.164163] sctp_association_free+0x2d0/0x930 [ 42.168731] ? sctp_asconf_queue_teardown+0x700/0x700 [ 42.173893] ? sock_def_wakeup+0x222/0x350 [ 42.178098] ? sk_dst_check+0x560/0x560 [ 42.182043] ? sctp_association_put+0x74/0x2f0 [ 42.186599] ? sctp_association_hold+0x20/0x20 [ 42.191176] ? __is_insn_slot_addr+0x1fc/0x330 [ 42.195729] ? sctp_sm_lookup_event+0x95/0x3c0 [ 42.200283] sctp_do_sm+0x28e7/0x6dd0 [ 42.204053] ? check_noncircular+0x20/0x20 [ 42.208266] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 42.214295] ? print_usage_bug+0x480/0x480 [ 42.218507] ? print_usage_bug+0x480/0x480 [ 42.222724] ? find_held_lock+0x35/0x1d0 [ 42.226761] ? skb_dequeue+0x12a/0x180 [ 42.230625] ? lock_downgrade+0x990/0x990 [ 42.234747] ? do_raw_spin_trylock+0x190/0x190 [ 42.239301] ? mark_held_locks+0xaf/0x100 [ 42.243424] ? trace_hardirqs_on+0xd/0x10 [ 42.247553] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 42.252116] sctp_close+0x3c6/0x980 [ 42.255721] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 42.260967] ? unwind_get_return_address+0x61/0xa0 [ 42.265868] ? __save_stack_trace+0x7e/0xd0 [ 42.270165] ? check_noncircular+0x20/0x20 [ 42.274376] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 42.278843] ? ipv6_sock_mc_close+0x148/0x1a0 [ 42.283316] ? ipv6_sock_ac_drop+0x580/0x580 [ 42.287693] ? ip_mc_drop_socket+0x1ce/0x230 [ 42.292071] ? __fsnotify_parent+0xb4/0x3a0 [ 42.296365] inet_release+0xed/0x1c0 [ 42.300051] inet6_release+0x50/0x70 [ 42.303736] sock_release+0x8d/0x1e0 [ 42.307427] ? sock_release+0x1e0/0x1e0 [ 42.311368] sock_close+0x16/0x20 [ 42.314789] __fput+0x327/0x7e0 [ 42.318044] ? fput+0x140/0x140 [ 42.321298] ? do_raw_spin_trylock+0x190/0x190 [ 42.325856] ? check_same_owner+0x320/0x320 [ 42.330153] ____fput+0x15/0x20 [ 42.333419] task_work_run+0x18a/0x260 [ 42.337278] ? task_work_cancel+0x210/0x210 [ 42.341581] ? _raw_spin_unlock+0x22/0x30 [ 42.345698] ? switch_task_namespaces+0x87/0xc0 [ 42.350341] do_exit+0xa3a/0x1b10 [ 42.353783] ? find_held_lock+0x35/0x1d0 [ 42.357821] ? lock_downgrade+0x990/0x990 [ 42.361940] ? mm_update_next_owner+0x930/0x930 [ 42.366580] ? __lock_is_held+0xb6/0x140 [ 42.370623] ? __fd_install+0x2f7/0x6a0 [ 42.374572] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.379303] ? get_unused_fd_flags+0x190/0x190 [ 42.383865] ? copy_user_generic_unrolled+0x89/0xc0 [ 42.388864] ? _copy_to_user+0xa2/0xc0 [ 42.392727] ? fd_install+0x4d/0x60 [ 42.396324] ? SYSC_accept4+0x4ec/0x850 [ 42.400280] ? kernel_accept+0x2f0/0x2f0 [ 42.404313] ? lock_downgrade+0x990/0x990 [ 42.408440] ? handle_mm_fault+0x4a2/0x860 [ 42.412645] ? __handle_mm_fault+0x3860/0x3860 [ 42.417194] ? vmacache_find+0x61/0x270 [ 42.421152] do_group_exit+0x149/0x400 [ 42.425020] ? SyS_exit+0x30/0x30 [ 42.428443] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 42.433429] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 42.438162] SyS_exit_group+0x1d/0x20 [ 42.441936] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 42.446659] RIP: 0033:0x43ea08 [ 42.449827] RSP: 002b:00007ffc4da2db38 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 42.457502] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ea08 [ 42.464746] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 42.471985] RBP: 0000000000000086 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 42.479231] R10: 000000000000001c R11: 0000000000000246 R12: 0000000000401730 [ 42.486471] R13: 00000000004017c0 R14: 0000000000000000 R15: 0000000000000000 [ 42.494206] Dumping ftrace buffer: [ 42.497774] (ftrace buffer empty) [ 42.501452] Kernel Offset: disabled [ 42.505051] Rebooting in 86400 seconds..