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-mmots-kasan-gce-7,10.128.15.209' (ECDSA) to the list of known hosts. executing program executing program executing program executing program executing program syzkaller login: [ 31.853286] refcount_t: underflow; use-after-free. [ 31.858377] ------------[ cut here ]------------ [ 31.863322] WARNING: CPU: 0 PID: 3044 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 31.872004] Kernel panic - not syncing: panic_on_warn set ... [ 31.872004] [ 31.879357] CPU: 0 PID: 3044 Comm: syzkaller752905 Not tainted 4.13.0-mm1+ #7 [ 31.886602] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 31.895927] Call Trace: [ 31.898490] dump_stack+0x194/0x257 [ 31.902090] ? arch_local_irq_restore+0x53/0x53 [ 31.906743] panic+0x1e4/0x417 [ 31.909908] ? __warn+0x1d9/0x1d9 [ 31.913330] ? show_regs_print_info+0x65/0x65 [ 31.917810] ? refcount_sub_and_test+0x167/0x1b0 [ 31.922545] __warn+0x1c4/0x1d9 [ 31.925796] ? refcount_sub_and_test+0x167/0x1b0 [ 31.930525] report_bug+0x211/0x2d0 [ 31.934132] fixup_bug+0x40/0x90 [ 31.937471] do_trap+0x260/0x390 [ 31.940817] do_error_trap+0x120/0x390 [ 31.944681] ? do_trap+0x390/0x390 [ 31.948194] ? refcount_sub_and_test+0x167/0x1b0 [ 31.952921] ? vprintk_emit+0x3ea/0x590 [ 31.956876] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 31.961707] do_invalid_op+0x1b/0x20 [ 31.965392] invalid_op+0x18/0x20 [ 31.968829] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 31.974247] RSP: 0018:ffff8801bfdce320 EFLAGS: 00010286 [ 31.979585] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 31.986828] RDX: 0000000000000026 RSI: 1ffff10037fb9c24 RDI: ffffed0037fb9c58 [ 31.994073] RBP: ffff8801bfdce3b0 R08: ffff8801bfdcda10 R09: 0000000000000000 [ 32.001315] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10037fb9c65 [ 32.008565] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801ce46ea24 [ 32.015831] ? refcount_inc+0x50/0x50 [ 32.019710] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 32.024438] ? sctp_association_free+0x2d0/0x930 [ 32.029166] ? sctp_do_sm+0x28e7/0x6dd0 [ 32.033112] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 32.037840] ? sctp_close+0x3c6/0x980 [ 32.041614] ? inet_release+0xed/0x1c0 [ 32.045478] sctp_wfree+0x183/0x620 [ 32.049085] ? __sctp_write_space+0x910/0x910 [ 32.053558] skb_release_head_state+0x124/0x200 [ 32.058202] skb_release_all+0x15/0x60 [ 32.062061] consume_skb+0x153/0x490 [ 32.065745] ? sctp_chunk_put+0x99/0x420 [ 32.069788] ? alloc_skb_with_frags+0x710/0x710 [ 32.074430] ? sctp_chunk_hold+0x20/0x20 [ 32.078469] ? refcount_sub_and_test+0x115/0x1b0 [ 32.083199] ? refcount_inc+0x50/0x50 [ 32.086974] ? mark_held_locks+0xb2/0x100 [ 32.091097] ? sctp_datamsg_put+0x456/0x560 [ 32.095399] sctp_chunk_put+0x29c/0x420 [ 32.099380] ? sctp_chunk_hold+0x20/0x20 [ 32.103420] ? sctp_transport_dst_confirm+0x50/0x50 [ 32.108427] sctp_chunk_free+0x53/0x60 [ 32.112289] __sctp_outq_teardown+0xc7d/0x15a0 [ 32.116846] ? sock_release+0x8d/0x1e0 [ 32.120715] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 32.125628] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 32.130622] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 32.135612] ? unwind_dump+0x4c0/0x4c0 [ 32.139470] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 32.144464] ? unwind_dump+0x4c0/0x4c0 [ 32.148337] ? check_noncircular+0x20/0x20 [ 32.152709] ? check_noncircular+0x20/0x20 [ 32.156926] ? unwind_get_return_address+0x61/0xa0 [ 32.161833] ? __save_stack_trace+0x61/0xd0 [ 32.166131] ? check_noncircular+0x20/0x20 [ 32.170341] ? print_usage_bug+0x480/0x480 [ 32.174555] ? find_held_lock+0x39/0x1d0 [ 32.178603] ? lock_downgrade+0x990/0x990 [ 32.182730] ? sk_dst_check+0x560/0x560 [ 32.186678] ? rcu_read_lock_sched_held+0x108/0x120 [ 32.191682] ? lock_release+0xd70/0xd70 [ 32.195635] sctp_outq_free+0x15/0x20 [ 32.199409] sctp_association_free+0x2d0/0x930 [ 32.203971] ? sctp_asconf_queue_teardown+0x700/0x700 [ 32.209136] ? sock_def_wakeup+0x222/0x350 [ 32.213342] ? sk_dst_check+0x560/0x560 [ 32.217294] ? sctp_association_put+0x74/0x2f0 [ 32.221850] ? sctp_association_hold+0x20/0x20 [ 32.226408] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 32.231574] ? lock_downgrade+0x990/0x990 [ 32.235692] ? sctp_sm_lookup_event+0x95/0x3c0 [ 32.240251] sctp_do_sm+0x28e7/0x6dd0 [ 32.244038] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 32.250070] ? __free_insn_slot+0x5c0/0x5c0 [ 32.254369] ? print_usage_bug+0x480/0x480 [ 32.258584] ? print_usage_bug+0x480/0x480 [ 32.262797] ? find_held_lock+0x39/0x1d0 [ 32.266859] ? lock_downgrade+0x990/0x990 [ 32.270989] ? skb_dequeue+0x22/0x180 [ 32.274772] ? do_raw_spin_trylock+0x190/0x190 [ 32.279348] ? mark_held_locks+0xb2/0x100 [ 32.283489] ? trace_hardirqs_on+0xd/0x10 [ 32.287617] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 32.292175] sctp_close+0x3c6/0x980 [ 32.295784] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 32.301050] ? dentry_free+0xcd/0x130 [ 32.304826] ? rcu_read_lock_sched_held+0x108/0x120 [ 32.309816] ? kmem_cache_free+0x249/0x280 [ 32.314025] ? dentry_free+0xd2/0x130 [ 32.317803] ? locks_remove_file+0x3fa/0x5a0 [ 32.322198] ? fcntl_setlk+0x10d0/0x10d0 [ 32.326243] ? __fsnotify_parent+0xb4/0x3a0 [ 32.330538] ? ip_mc_drop_socket+0x1ce/0x230 [ 32.334925] inet_release+0xed/0x1c0 [ 32.338613] sock_release+0x8d/0x1e0 [ 32.342299] ? sock_release+0x1e0/0x1e0 [ 32.346249] sock_close+0x16/0x20 [ 32.349676] __fput+0x333/0x7f0 [ 32.352934] ? fput+0x140/0x140 [ 32.356190] ? check_same_owner+0x320/0x320 [ 32.360495] ? _raw_spin_unlock_irq+0x27/0x70 [ 32.364981] ____fput+0x15/0x20 [ 32.368234] task_work_run+0x199/0x270 [ 32.372096] ? task_work_cancel+0x210/0x210 [ 32.376394] ? _raw_spin_unlock+0x22/0x30 [ 32.380517] ? switch_task_namespaces+0x87/0xc0 [ 32.385179] do_exit+0xa52/0x1b40 [ 32.388621] ? check_noncircular+0x20/0x20 [ 32.392831] ? lock_page_memcg+0x3b0/0x3b0 [ 32.397041] ? __lock_is_held+0xbc/0x140 [ 32.401080] ? mm_update_next_owner+0x930/0x930 [ 32.405726] ? lru_cache_add+0x1c7/0x3a0 [ 32.409770] ? get_mem_cgroup_from_mm+0x710/0x710 [ 32.414585] ? lru_cache_add_file+0x20/0x20 [ 32.418892] ? __lock_acquire+0x732/0x4620 [ 32.423105] ? lock_downgrade+0x990/0x990 [ 32.427234] ? check_noncircular+0x20/0x20 [ 32.431443] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 32.436606] ? do_raw_spin_trylock+0x190/0x190 [ 32.441177] ? lockdep_init_map+0x3d/0x70 [ 32.445333] ? find_held_lock+0x39/0x1d0 [ 32.449389] ? lock_downgrade+0x990/0x990 [ 32.453510] ? recalc_sigpending_tsk+0x117/0x150 [ 32.458238] ? recalc_sigpending+0x103/0x160 [ 32.462616] ? recalc_sigpending_tsk+0x150/0x150 [ 32.467340] ? get_signal+0x397/0x17e0 [ 32.471209] do_group_exit+0x149/0x400 [ 32.475066] ? __lock_is_held+0xbc/0x140 [ 32.479100] ? SyS_exit+0x30/0x30 [ 32.482531] ? _raw_spin_unlock_irq+0x27/0x70 [ 32.487004] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.492009] get_signal+0x7e8/0x17e0 [ 32.495724] ? ptrace_notify+0x130/0x130 [ 32.499762] ? get_unused_fd_flags+0x190/0x190 [ 32.504338] ? __lock_is_held+0xbc/0x140 [ 32.508384] do_signal+0x94/0x1ee0 [ 32.511896] ? __fd_install+0x2f7/0x6a0 [ 32.515850] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 32.520583] ? get_unused_fd_flags+0x190/0x190 [ 32.525145] ? setup_sigcontext+0x7d0/0x7d0 [ 32.529448] ? copy_user_generic_unrolled+0x89/0xc0 [ 32.534439] ? _copy_to_user+0xa2/0xc0 [ 32.538303] ? fd_install+0x4d/0x60 [ 32.541898] ? fput+0xd2/0x140 [ 32.545063] ? SYSC_accept4+0x4f2/0x850 [ 32.549011] ? exit_to_usermode_loop+0x98/0x300 [ 32.553656] exit_to_usermode_loop+0x224/0x300 [ 32.558214] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 32.563720] ? _raw_spin_unlock_irq+0x27/0x70 [ 32.568187] ? __do_page_fault+0xb60/0xb60 [ 32.572391] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.577381] syscall_return_slowpath+0x42f/0x500 [ 32.582108] ? finish_task_switch+0x1aa/0x740 [ 32.586572] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 32.591559] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 32.596470] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 32.601456] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 32.606189] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 32.610913] RIP: 0033:0x447429 [ 32.614074] RSP: 002b:00007f2e79e12dc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 32.621764] RAX: 0000000000000004 RBX: 0000000000000000 RCX: 0000000000447429 [ 32.629014] RDX: 000000002048bffc RSI: 0000000020b4afe4 RDI: 0000000000000003 [ 32.636265] RBP: 0000000000000000 R08: 00007f2e79e13700 R09: 00007f2e79e13700 [ 32.643520] R10: 00007f2e79e13700 R11: 0000000000000202 R12: 0000000000000000 [ 32.650761] R13: 00000000007efd4f R14: 00007f2e79e139c0 R15: 0000000000000000 [ 32.658168] Dumping ftrace buffer: [ 32.661733] (ftrace buffer empty) [ 32.665425] Kernel Offset: disabled [ 32.669040] Rebooting in 86400 seconds..