serialport: Connected to syzkaller.us-central1-c.ci-upstream-kasan-gce-4 port 1 (session ID: a7ef1cd2b341dc4890b01f7dd2ff9b74d0053821ccd545245e71ac32427674c0, active connections: 1). 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-4,10.128.0.57' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 31.589644] refcount_t: underflow; use-after-free. [ 31.590684] ------------[ cut here ]------------ [ 31.591592] WARNING: CPU: 0 PID: 2920 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 31.592765] Kernel panic - not syncing: panic_on_warn set ... [ 31.592765] [ 31.593739] CPU: 0 PID: 2920 Comm: syzkaller031041 Not tainted 4.13.0-rc3+ #17 [ 31.594791] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.596012] Call Trace: [ 31.596378] dump_stack+0x194/0x257 [ 31.596932] ? arch_local_irq_restore+0x53/0x53 [ 31.597624] panic+0x1e4/0x417 [ 31.598060] ? __warn+0x1d9/0x1d9 [ 31.598662] ? show_regs_print_info+0x65/0x65 [ 31.599291] ? refcount_sub_and_test+0x167/0x1b0 [ 31.599926] __warn+0x1c4/0x1d9 [ 31.600373] ? refcount_sub_and_test+0x167/0x1b0 [ 31.601038] report_bug+0x211/0x2d0 [ 31.601537] fixup_bug+0x40/0x90 [ 31.602029] do_trap+0x260/0x390 [ 31.602514] do_error_trap+0x120/0x390 [ 31.603040] ? do_trap+0x390/0x390 [ 31.603519] ? refcount_sub_and_test+0x167/0x1b0 [ 31.604152] ? vprintk_emit+0x3ea/0x590 [ 31.604789] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.605516] do_invalid_op+0x1b/0x20 [ 31.606019] invalid_op+0x1e/0x30 [ 31.606490] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 31.607201] RSP: 0018:ffff8801c1ae6330 EFLAGS: 00010286 [ 31.607991] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 31.608945] RDX: 0000000000000026 RSI: 1ffff1003835cc26 RDI: ffffed003835cc5a [ 31.610696] RBP: ffff8801c1ae63c0 R08: 0000000000000001 R09: 0000000000000000 [ 31.617933] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003835cc67 [ 31.625169] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d6b5c27c [ 31.632443] ? refcount_inc+0x50/0x50 [ 31.636211] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 31.640938] ? sctp_association_free+0x2d0/0x930 [ 31.645746] ? sctp_do_sm+0x28e7/0x6d90 [ 31.649688] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 31.654413] ? sctp_close+0x3c6/0x980 [ 31.658186] ? inet_release+0xed/0x1c0 [ 31.662046] sctp_wfree+0x183/0x620 [ 31.665643] ? __sctp_write_space+0x910/0x910 [ 31.670109] skb_release_head_state+0x124/0x200 [ 31.674745] skb_release_all+0x15/0x60 [ 31.678600] consume_skb+0x153/0x490 [ 31.682278] ? sctp_chunk_put+0x99/0x420 [ 31.686314] ? pskb_carve+0x1db0/0x1db0 [ 31.690254] ? sctp_chunk_hold+0x20/0x20 [ 31.694300] ? refcount_sub_and_test+0x115/0x1b0 [ 31.699034] ? refcount_inc+0x50/0x50 [ 31.702802] ? mark_held_locks+0xaf/0x100 [ 31.706921] ? sctp_datamsg_put+0x456/0x560 [ 31.711225] sctp_chunk_put+0x29c/0x420 [ 31.715168] ? sctp_chunk_hold+0x20/0x20 [ 31.719200] ? sctp_transport_dst_confirm+0x50/0x50 [ 31.724189] ? noop_count+0x40/0x40 [ 31.727790] sctp_chunk_free+0x53/0x60 [ 31.731645] __sctp_outq_teardown+0xc7d/0x15a0 [ 31.736201] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 31.741099] ? lock_downgrade+0x990/0x990 [ 31.745215] ? lock_release+0xa40/0xa40 [ 31.749161] ? __free_insn_slot+0x5c0/0x5c0 [ 31.753452] ? update_stack_state+0x700/0x700 [ 31.757920] ? print_usage_bug+0x480/0x480 [ 31.762133] ? is_bpf_text_address+0xa4/0x120 [ 31.766608] ? __kernel_text_address+0xae/0xe0 [ 31.771159] ? unwind_get_return_address+0x61/0xa0 [ 31.776056] ? __save_stack_trace+0x7e/0xd0 [ 31.780350] ? check_noncircular+0x20/0x20 [ 31.784551] ? print_usage_bug+0x480/0x480 [ 31.788778] ? SOFTIRQ_verbose+0x10/0x10 [ 31.792805] ? save_stack_trace+0x16/0x20 [ 31.796920] ? save_trace+0x11f/0x350 [ 31.800706] ? lock_acquire+0x1d5/0x580 [ 31.804646] ? lock_acquire+0x1d5/0x580 [ 31.808589] ? lock_timer_base+0x1a3/0x2b0 [ 31.812794] ? find_held_lock+0x35/0x1d0 [ 31.816831] ? sock_def_wakeup+0x1f9/0x350 [ 31.821032] ? lock_downgrade+0x990/0x990 [ 31.825147] ? lock_release+0xa40/0xa40 [ 31.829092] sctp_outq_free+0x15/0x20 [ 31.832861] sctp_association_free+0x2d0/0x930 [ 31.837417] ? sctp_asconf_queue_teardown+0x700/0x700 [ 31.842578] ? sock_def_wakeup+0x222/0x350 [ 31.846781] ? sk_dst_check+0x560/0x560 [ 31.850724] ? sctp_association_put+0x74/0x2f0 [ 31.855272] ? sctp_association_hold+0x20/0x20 [ 31.859826] ? print_usage_bug+0x480/0x480 [ 31.864027] ? sctp_sm_lookup_event+0x95/0x3c0 [ 31.868590] sctp_do_sm+0x28e7/0x6d90 [ 31.872370] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 31.878400] ? get_signal+0x7e8/0x17e0 [ 31.882258] ? print_usage_bug+0x480/0x480 [ 31.886461] ? check_noncircular+0x20/0x20 [ 31.890671] ? print_usage_bug+0x480/0x480 [ 31.894889] ? find_held_lock+0x35/0x1d0 [ 31.898923] ? skb_dequeue+0x12a/0x180 [ 31.902778] ? lock_downgrade+0x990/0x990 [ 31.906895] ? do_raw_spin_trylock+0x190/0x190 [ 31.911447] ? mark_held_locks+0xaf/0x100 [ 31.915571] ? trace_hardirqs_on+0xd/0x10 [ 31.919694] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 31.924247] sctp_close+0x3c6/0x980 [ 31.927851] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 31.933095] ? trace_hardirqs_off+0xd/0x10 [ 31.937296] ? _raw_spin_unlock_irqrestore+0xa6/0xba [ 31.942368] ? check_noncircular+0x20/0x20 [ 31.946576] ? locks_remove_file+0x414/0x560 [ 31.950953] ? fcntl_setlk+0x10c0/0x10c0 [ 31.954979] ? free_fs_struct+0x4f/0x60 [ 31.958921] ? __fsnotify_parent+0xb4/0x3a0 [ 31.963215] ? ip_mc_drop_socket+0x1ce/0x230 [ 31.967595] inet_release+0xed/0x1c0 [ 31.971279] sock_release+0x8d/0x1e0 [ 31.974959] ? sock_release+0x1e0/0x1e0 [ 31.978898] sock_close+0x16/0x20 [ 31.982318] __fput+0x327/0x7e0 [ 31.985569] ? fput+0x140/0x140 [ 31.988817] ? do_raw_spin_trylock+0x190/0x190 [ 31.993367] ? check_same_owner+0x320/0x320 [ 31.997658] ____fput+0x15/0x20 [ 32.000906] task_work_run+0x18a/0x260 [ 32.004765] ? task_work_cancel+0x210/0x210 [ 32.009062] ? _raw_spin_unlock+0x22/0x30 [ 32.013178] ? switch_task_namespaces+0x87/0xc0 [ 32.017819] do_exit+0xa32/0x1b10 [ 32.021240] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 32.026398] ? page_add_new_anon_rmap+0x36c/0x750 [ 32.031218] ? exit_notify+0xb10/0xb10 [ 32.035083] ? do_huge_pmd_anonymous_page+0xa32/0x1890 [ 32.040326] ? lock_downgrade+0x990/0x990 [ 32.044440] ? pudp_huge_clear_flush+0x1f0/0x1f0 [ 32.049168] ? do_raw_spin_trylock+0x190/0x190 [ 32.053729] ? __lock_acquire+0x6ef/0x3dc0 [ 32.057932] ? _raw_spin_unlock+0x22/0x30 [ 32.062052] ? do_huge_pmd_anonymous_page+0xa9a/0x1890 [ 32.067304] ? check_noncircular+0x20/0x20 [ 32.071523] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 32.076686] ? find_held_lock+0x35/0x1d0 [ 32.080722] ? get_signal+0x855/0x17e0 [ 32.084577] ? lock_downgrade+0x990/0x990 [ 32.088699] do_group_exit+0x149/0x400 [ 32.092554] ? __lock_is_held+0xb6/0x140 [ 32.096581] ? SyS_exit+0x30/0x30 [ 32.100000] ? _raw_spin_unlock_irq+0x27/0x70 [ 32.104472] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.109461] get_signal+0x7e8/0x17e0 [ 32.113170] ? ptrace_notify+0x130/0x130 [ 32.117203] ? __fd_install+0x2da/0x6a0 [ 32.121145] ? lock_downgrade+0x990/0x990 [ 32.125267] ? __lock_is_held+0xb6/0x140 [ 32.129310] do_signal+0x94/0x1ee0 [ 32.132818] ? __fd_install+0x2f7/0x6a0 [ 32.136763] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 32.141492] ? get_unused_fd_flags+0x190/0x190 [ 32.146044] ? setup_sigcontext+0x7d0/0x7d0 [ 32.150346] ? copy_user_generic_unrolled+0x89/0xc0 [ 32.155331] ? _copy_to_user+0xa2/0xc0 [ 32.159190] ? fd_install+0x4d/0x60 [ 32.162786] ? fput+0xd2/0x140 [ 32.165950] ? SYSC_accept4+0x4ec/0x850 [ 32.169893] ? exit_to_usermode_loop+0x98/0x2d0 [ 32.174534] exit_to_usermode_loop+0x21c/0x2d0 [ 32.179086] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 32.184595] ? __do_page_fault+0x2b8/0xb60 [ 32.188803] syscall_return_slowpath+0x3a7/0x450 [ 32.193527] ? prepare_exit_to_usermode+0x220/0x220 [ 32.198512] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 32.203411] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.208391] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 32.213118] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 32.217839] RIP: 0033:0x445499 [ 32.220995] RSP: 002b:00007f867e8afdc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 32.228669] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000445499 [ 32.235904] RDX: 0000000020ade000 RSI: 00000000201b4ff0 RDI: 0000000000000003 [ 32.243142] RBP: 0000000000000000 R08: 00007f867e8b0700 R09: 00007f867e8b0700 [ 32.250379] R10: 00007f867e8b0700 R11: 0000000000000202 R12: 0000000000000000 [ 32.257615] R13: 00007ffcca28173f R14: 00007f867e8b09c0 R15: 0000000000000000 [ 32.265486] Dumping ftrace buffer: [ 32.269050] (ftrace buffer empty) [ 32.272728] Kernel Offset: disabled [ 32.276326] Rebooting in 86400 seconds..