serialport: Connected to syzkaller.us-central1-c.ci-upstream-kasan-gce-9 port 1 (session ID: f43fba25edba98821ab5cea5e72e9f5974ef4357a4609c8c0235554afbd65ab3, 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-9,10.128.0.34' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 36.029486] refcount_t: underflow; use-after-free. [ 36.030394] ------------[ cut here ]------------ [ 36.031237] WARNING: CPU: 0 PID: 2922 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 36.032428] Kernel panic - not syncing: panic_on_warn set ... [ 36.032428] [ 36.033422] CPU: 0 PID: 2922 Comm: syzkaller108695 Not tainted 4.13.0-rc3+ #22 [ 36.034388] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 36.035628] Call Trace: [ 36.035990] dump_stack+0x194/0x257 [ 36.036483] ? arch_local_irq_restore+0x53/0x53 [ 36.037117] panic+0x1e4/0x417 [ 36.037584] ? __warn+0x1d9/0x1d9 [ 36.038052] ? show_regs_print_info+0x65/0x65 [ 36.038665] ? refcount_sub_and_test+0x167/0x1b0 [ 36.039299] __warn+0x1c4/0x1d9 [ 36.039745] ? refcount_sub_and_test+0x167/0x1b0 [ 36.040381] report_bug+0x211/0x2d0 [ 36.040904] fixup_bug+0x40/0x90 [ 36.041425] do_trap+0x260/0x390 [ 36.041890] do_error_trap+0x120/0x390 [ 36.042435] ? do_trap+0x390/0x390 [ 36.042915] ? refcount_sub_and_test+0x167/0x1b0 [ 36.043582] ? vprintk_emit+0x3ea/0x590 [ 36.044123] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 36.044783] do_invalid_op+0x1b/0x20 [ 36.045297] invalid_op+0x1e/0x30 [ 36.045763] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 36.046540] RSP: 0018:ffff8801d2566330 EFLAGS: 00010286 [ 36.047263] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 36.048215] RDX: 0000000000000026 RSI: 1ffff1003a4acc26 RDI: ffffed003a4acc5a [ 36.049196] RBP: ffff8801d25663c0 R08: 0000000000000001 R09: 0000000000000000 [ 36.053651] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a4acc67 [ 36.060885] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d06309fc [ 36.068144] ? refcount_inc+0x50/0x50 [ 36.071910] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 36.076637] ? sctp_association_free+0x2d0/0x930 [ 36.081358] ? sctp_do_sm+0x28e7/0x6d90 [ 36.085297] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 36.090018] ? sctp_close+0x3c6/0x980 [ 36.093784] ? inet_release+0xed/0x1c0 [ 36.097645] sctp_wfree+0x183/0x620 [ 36.101247] ? __sctp_write_space+0x910/0x910 [ 36.105709] skb_release_head_state+0x124/0x200 [ 36.110343] skb_release_all+0x15/0x60 [ 36.114200] consume_skb+0x153/0x490 [ 36.117881] ? sctp_chunk_put+0x99/0x420 [ 36.121908] ? pskb_carve+0x1db0/0x1db0 [ 36.125848] ? sctp_chunk_hold+0x20/0x20 [ 36.129878] ? refcount_sub_and_test+0x115/0x1b0 [ 36.134600] ? refcount_inc+0x50/0x50 [ 36.138367] ? mark_held_locks+0xaf/0x100 [ 36.142486] ? sctp_datamsg_put+0x456/0x560 [ 36.146780] sctp_chunk_put+0x29c/0x420 [ 36.150721] ? sctp_chunk_hold+0x20/0x20 [ 36.154754] ? sctp_transport_dst_confirm+0x50/0x50 [ 36.159744] ? noop_count+0x40/0x40 [ 36.163346] sctp_chunk_free+0x53/0x60 [ 36.167203] __sctp_outq_teardown+0xc7d/0x15a0 [ 36.171758] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 36.176654] ? lock_downgrade+0x990/0x990 [ 36.180771] ? lock_release+0xa40/0xa40 [ 36.184714] ? __free_insn_slot+0x5c0/0x5c0 [ 36.189003] ? update_stack_state+0x700/0x700 [ 36.193463] ? print_usage_bug+0x480/0x480 [ 36.197671] ? is_bpf_text_address+0xa4/0x120 [ 36.202134] ? __kernel_text_address+0xae/0xe0 [ 36.206682] ? unwind_get_return_address+0x61/0xa0 [ 36.211577] ? __save_stack_trace+0x7e/0xd0 [ 36.215867] ? check_noncircular+0x20/0x20 [ 36.220067] ? print_usage_bug+0x480/0x480 [ 36.224266] ? SOFTIRQ_verbose+0x10/0x10 [ 36.228290] ? save_stack_trace+0x16/0x20 [ 36.232401] ? save_trace+0x11f/0x350 [ 36.236170] ? lock_acquire+0x1d5/0x580 [ 36.240107] ? lock_acquire+0x1d5/0x580 [ 36.244058] ? lock_timer_base+0x1a3/0x2b0 [ 36.248263] ? find_held_lock+0x35/0x1d0 [ 36.252298] ? sock_def_wakeup+0x1f9/0x350 [ 36.256497] ? lock_downgrade+0x990/0x990 [ 36.260615] ? lock_release+0xa40/0xa40 [ 36.264562] sctp_outq_free+0x15/0x20 [ 36.268334] sctp_association_free+0x2d0/0x930 [ 36.272888] ? sctp_asconf_queue_teardown+0x700/0x700 [ 36.278045] ? sock_def_wakeup+0x222/0x350 [ 36.282247] ? sk_dst_check+0x560/0x560 [ 36.286188] ? sctp_association_put+0x74/0x2f0 [ 36.290738] ? sctp_association_hold+0x20/0x20 [ 36.295294] ? print_usage_bug+0x480/0x480 [ 36.299499] ? find_held_lock+0x35/0x1d0 [ 36.303527] ? sctp_sm_lookup_event+0x95/0x3c0 [ 36.308081] sctp_do_sm+0x28e7/0x6d90 [ 36.311862] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 36.317890] ? print_usage_bug+0x480/0x480 [ 36.322094] ? print_usage_bug+0x480/0x480 [ 36.326314] ? find_held_lock+0x35/0x1d0 [ 36.330350] ? skb_dequeue+0x12a/0x180 [ 36.334216] ? lock_downgrade+0x990/0x990 [ 36.338343] ? do_raw_spin_trylock+0x190/0x190 [ 36.342898] ? mark_held_locks+0xaf/0x100 [ 36.347019] ? trace_hardirqs_on+0xd/0x10 [ 36.351147] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 36.355699] sctp_close+0x3c6/0x980 [ 36.359302] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 36.364543] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 36.369524] ? trace_hardirqs_on+0xd/0x10 [ 36.373645] ? rcu_idle_enter+0x1a0/0x1a0 [ 36.377763] ? locks_remove_file+0x414/0x560 [ 36.382142] ? fcntl_setlk+0x10c0/0x10c0 [ 36.386172] ? find_held_lock+0x35/0x1d0 [ 36.390201] ? __fsnotify_parent+0xb4/0x3a0 [ 36.394489] ? ip_mc_drop_socket+0x1ce/0x230 [ 36.398871] inet_release+0xed/0x1c0 [ 36.402558] sock_release+0x8d/0x1e0 [ 36.406238] ? sock_release+0x1e0/0x1e0 [ 36.410176] sock_close+0x16/0x20 [ 36.413596] __fput+0x327/0x7e0 [ 36.416846] ? fput+0x140/0x140 [ 36.420095] ? check_same_owner+0x320/0x320 [ 36.424389] ____fput+0x15/0x20 [ 36.427636] task_work_run+0x18a/0x260 [ 36.431495] ? task_work_cancel+0x210/0x210 [ 36.435785] ? free_nsproxy+0x185/0x1f0 [ 36.439725] ? switch_task_namespaces+0xa2/0xc0 [ 36.444366] do_exit+0xa32/0x1b10 [ 36.447789] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 36.452945] ? page_add_new_anon_rmap+0x36c/0x750 [ 36.457767] ? exit_notify+0xb10/0xb10 [ 36.461630] ? do_huge_pmd_anonymous_page+0xa32/0x1890 [ 36.466872] ? lock_downgrade+0x990/0x990 [ 36.470990] ? pudp_huge_clear_flush+0x1f0/0x1f0 [ 36.475718] ? do_raw_spin_trylock+0x190/0x190 [ 36.480280] ? __lock_acquire+0x6ef/0x3dc0 [ 36.484482] ? _raw_spin_unlock+0x22/0x30 [ 36.488597] ? do_huge_pmd_anonymous_page+0xa9a/0x1890 [ 36.493849] ? check_noncircular+0x20/0x20 [ 36.498066] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 36.503230] ? find_held_lock+0x35/0x1d0 [ 36.507267] ? get_signal+0x855/0x17e0 [ 36.511130] ? lock_downgrade+0x990/0x990 [ 36.515256] do_group_exit+0x149/0x400 [ 36.519125] ? __lock_is_held+0xb6/0x140 [ 36.523156] ? SyS_exit+0x30/0x30 [ 36.526577] ? _raw_spin_unlock_irq+0x27/0x70 [ 36.531045] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 36.536033] get_signal+0x7e8/0x17e0 [ 36.539740] ? ptrace_notify+0x130/0x130 [ 36.543782] ? __fd_install+0x2da/0x6a0 [ 36.547724] ? lock_downgrade+0x990/0x990 [ 36.551847] ? __lock_is_held+0xb6/0x140 [ 36.555899] do_signal+0x94/0x1ee0 [ 36.559418] ? __fd_install+0x2f7/0x6a0 [ 36.563365] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 36.568098] ? get_unused_fd_flags+0x190/0x190 [ 36.572656] ? setup_sigcontext+0x7d0/0x7d0 [ 36.576954] ? copy_user_generic_unrolled+0x89/0xc0 [ 36.581942] ? _copy_to_user+0xa2/0xc0 [ 36.585801] ? fd_install+0x4d/0x60 [ 36.589393] ? fput+0xd2/0x140 [ 36.592555] ? SYSC_accept4+0x4ec/0x850 [ 36.596500] ? exit_to_usermode_loop+0x98/0x2d0 [ 36.601141] exit_to_usermode_loop+0x21c/0x2d0 [ 36.605693] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 36.611201] ? __do_page_fault+0x2b8/0xb60 [ 36.615406] syscall_return_slowpath+0x3a7/0x450 [ 36.620128] ? prepare_exit_to_usermode+0x220/0x220 [ 36.625114] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 36.630012] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 36.634993] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 36.639720] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 36.644440] RIP: 0033:0x445d69 [ 36.647594] RSP: 002b:00007fe971c24dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 36.655268] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000445d69 [ 36.662504] RDX: 0000000020ade000 RSI: 00000000201b4ff0 RDI: 0000000000000003 [ 36.669738] RBP: 0000000000000000 R08: 00007fe971c25700 R09: 00007fe971c25700 [ 36.676971] R10: 00007fe971c25700 R11: 0000000000000202 R12: 0000000000000000 [ 36.684206] R13: 00000000007efe6f R14: 00007fe971c259c0 R15: 0000000000000000 [ 36.691660] Dumping ftrace buffer: [ 36.695259] (ftrace buffer empty) [ 36.698937] Kernel Offset: disabled [ 36.702534] Rebooting in 86400 seconds..