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-next-kasan-gce-1,10.128.15.206' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 47.451058] refcount_t: underflow; use-after-free. [ 47.451874] ------------[ cut here ]------------ [ 47.452671] WARNING: CPU: 0 PID: 3036 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 47.453844] Kernel panic - not syncing: panic_on_warn set ... [ 47.453844] [ 47.454879] CPU: 0 PID: 3036 Comm: syzkaller403795 Not tainted 4.13.0-rc5-next-20170817+ #5 [ 47.456014] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 47.457234] Call Trace: [ 47.457592] dump_stack+0x194/0x257 [ 47.458100] ? arch_local_irq_restore+0x53/0x53 [ 47.458733] panic+0x1e4/0x417 [ 47.459169] ? __warn+0x1d9/0x1d9 [ 47.459635] ? show_regs_print_info+0x65/0x65 [ 47.460247] ? refcount_sub_and_test+0x167/0x1b0 [ 47.460880] __warn+0x1c4/0x1d9 [ 47.461322] ? refcount_sub_and_test+0x167/0x1b0 [ 47.461961] report_bug+0x211/0x2d0 [ 47.462455] fixup_bug+0x40/0x90 [ 47.462925] do_trap+0x260/0x390 [ 47.463388] do_error_trap+0x120/0x390 [ 47.463926] ? do_trap+0x390/0x390 [ 47.464418] ? refcount_sub_and_test+0x167/0x1b0 [ 47.465090] ? vprintk_emit+0x3ea/0x590 [ 47.465632] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 47.466297] do_invalid_op+0x1b/0x20 [ 47.466810] invalid_op+0x18/0x20 [ 47.467273] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 47.468043] RSP: 0018:ffff8801cf3a6840 EFLAGS: 00010282 [ 47.468872] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 47.469868] RDX: 0000000000000026 RSI: 1ffff10039e74cc8 RDI: ffffed0039e74cfc [ 47.470871] RBP: ffff8801cf3a68d0 R08: 0000000000000001 R09: 0000000000000000 [ 47.476234] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039e74d09 [ 47.483489] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d244d2bc [ 47.490758] ? refcount_inc+0x50/0x50 [ 47.494528] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 47.499262] ? sctp_association_free+0x2d0/0x930 [ 47.503996] ? sctp_do_sm+0x28e7/0x6d90 [ 47.507936] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 47.512664] ? sctp_close+0x3c6/0x980 [ 47.516434] ? inet_release+0xed/0x1c0 [ 47.520295] sctp_wfree+0x183/0x620 [ 47.523894] ? __sctp_write_space+0x910/0x910 [ 47.528362] skb_release_head_state+0x124/0x200 [ 47.532999] skb_release_all+0x15/0x60 [ 47.536853] consume_skb+0x153/0x490 [ 47.540547] ? sctp_chunk_put+0x99/0x420 [ 47.544605] ? alloc_skb_with_frags+0x710/0x710 [ 47.549241] ? sctp_chunk_hold+0x20/0x20 [ 47.553282] ? refcount_sub_and_test+0x115/0x1b0 [ 47.558012] ? refcount_inc+0x50/0x50 [ 47.561784] ? mark_held_locks+0xaf/0x100 [ 47.565903] ? sctp_datamsg_put+0x456/0x560 [ 47.570199] sctp_chunk_put+0x29c/0x420 [ 47.574144] ? sctp_chunk_hold+0x20/0x20 [ 47.578177] ? sctp_transport_dst_confirm+0x50/0x50 [ 47.583164] ? retint_kernel+0x10/0x10 [ 47.587031] sctp_chunk_free+0x53/0x60 [ 47.590894] __sctp_outq_teardown+0xc7d/0x15a0 [ 47.595446] ? lock_downgrade+0x990/0x990 [ 47.599568] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 47.604465] ? unwind_dump+0x4c0/0x4c0 [ 47.608335] ? is_bpf_text_address+0xa4/0x120 [ 47.612800] ? __kernel_text_address+0xae/0xe0 [ 47.617370] ? unwind_get_return_address+0x61/0xa0 [ 47.622273] ? __save_stack_trace+0x7e/0xd0 [ 47.626570] ? add_lock_to_list.isra.35+0x1ff/0x4f0 [ 47.631556] ? SOFTIRQ_verbose+0x10/0x10 [ 47.635592] ? save_stack_trace+0x16/0x20 [ 47.639709] ? save_trace+0x11f/0x350 [ 47.643497] ? __free_insn_slot+0x5c0/0x5c0 [ 47.647792] ? check_noncircular+0x20/0x20 [ 47.651997] ? print_usage_bug+0x480/0x480 [ 47.656208] ? lock_acquire+0x1d5/0x580 [ 47.660149] ? lock_acquire+0x1d5/0x580 [ 47.664095] ? lock_timer_base+0x1a3/0x2b0 [ 47.668303] ? find_held_lock+0x35/0x1d0 [ 47.672342] ? sock_def_wakeup+0x1f9/0x350 [ 47.676545] ? lock_downgrade+0x990/0x990 [ 47.680663] ? lock_release+0xa40/0xa40 [ 47.684609] sctp_outq_free+0x15/0x20 [ 47.688383] sctp_association_free+0x2d0/0x930 [ 47.692939] ? sctp_asconf_queue_teardown+0x700/0x700 [ 47.698099] ? sock_def_wakeup+0x222/0x350 [ 47.702302] ? sk_dst_check+0x560/0x560 [ 47.706252] ? sctp_association_put+0x74/0x2f0 [ 47.710802] ? sctp_association_hold+0x20/0x20 [ 47.715356] ? print_usage_bug+0x480/0x480 [ 47.719561] ? sctp_sm_lookup_event+0x95/0x3c0 [ 47.724121] sctp_do_sm+0x28e7/0x6d90 [ 47.727900] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 47.733939] ? print_usage_bug+0x480/0x480 [ 47.738145] ? print_usage_bug+0x480/0x480 [ 47.742355] ? print_usage_bug+0x480/0x480 [ 47.746566] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 47.751727] ? find_held_lock+0x35/0x1d0 [ 47.755763] ? skb_dequeue+0x12a/0x180 [ 47.759618] ? lock_downgrade+0x990/0x990 [ 47.763737] ? do_raw_spin_trylock+0x190/0x190 [ 47.768293] ? mark_held_locks+0xaf/0x100 [ 47.772417] ? trace_hardirqs_on+0xd/0x10 [ 47.776539] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 47.781091] sctp_close+0x3c6/0x980 [ 47.784693] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 47.789961] ? check_noncircular+0x20/0x20 [ 47.794182] ? debug_check_no_locks_freed+0x3c0/0x3c0 [ 47.799347] ? locks_remove_file+0x3fa/0x5a0 [ 47.803728] ? fcntl_setlk+0x10c0/0x10c0 [ 47.807759] ? __fsnotify_parent+0xb4/0x3a0 [ 47.812052] ? ip_mc_drop_socket+0x1ce/0x230 [ 47.816435] inet_release+0xed/0x1c0 [ 47.820121] sock_release+0x8d/0x1e0 [ 47.823811] ? sock_release+0x1e0/0x1e0 [ 47.827759] sock_close+0x16/0x20 [ 47.831180] __fput+0x327/0x7e0 [ 47.834432] ? fput+0x140/0x140 [ 47.837681] ? _raw_spin_unlock_irq+0x27/0x70 [ 47.842156] ____fput+0x15/0x20 [ 47.845409] task_work_run+0x199/0x270 [ 47.849265] ? task_work_cancel+0x210/0x210 [ 47.853556] ? _raw_spin_unlock_irqrestore+0x31/0xba [ 47.858640] get_signal+0x143d/0x17e0 [ 47.862415] ? cmp_ex_sort+0xb0/0xb0 [ 47.866101] ? search_extable+0x35/0x40 [ 47.870049] ? copy_user_handle_tail+0x40/0x80 [ 47.874595] ? copy_user_handle_tail+0x40/0x80 [ 47.879144] ? ex_handler_default+0x18/0x90 [ 47.883433] ? __pte+0x60/0x60 [ 47.886599] ? fixup_exception+0x93/0xc0 [ 47.890645] ? pgtable_bad+0x110/0x110 [ 47.894502] ? ptrace_notify+0x130/0x130 [ 47.898533] ? check_noncircular+0x20/0x20 [ 47.902741] ? __bad_area_nosemaphore+0x1f4/0x3e0 [ 47.907559] ? rcu_note_context_switch+0x710/0x710 [ 47.912458] ? downgrade_write+0x150/0x150 [ 47.916664] ? check_noncircular+0x20/0x20 [ 47.920867] ? bad_area+0x69/0x80 [ 47.924300] ? retint_kernel+0x10/0x10 [ 47.928164] do_signal+0x94/0x1ee0 [ 47.931679] ? put_unused_fd+0x62/0x70 [ 47.935539] ? setup_sigcontext+0x7d0/0x7d0 [ 47.939828] ? do_raw_spin_trylock+0x190/0x190 [ 47.944391] ? __put_unused_fd+0x183/0x250 [ 47.948597] ? alloc_fdtable+0x280/0x280 [ 47.952625] ? cpumask_weight.constprop.3+0x45/0x45 [ 47.957635] ? _copy_to_user+0xa2/0xc0 [ 47.961494] ? _raw_spin_unlock+0x22/0x30 [ 47.965611] ? put_unused_fd+0x62/0x70 [ 47.969460] ? fput+0xd2/0x140 [ 47.972633] ? SYSC_accept4+0x4ec/0x850 [ 47.976577] ? exit_to_usermode_loop+0x98/0x300 [ 47.981223] exit_to_usermode_loop+0x224/0x300 [ 47.985778] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 47.991298] ? handle_mm_fault+0x4e3/0x940 [ 47.995534] syscall_return_slowpath+0x42f/0x500 [ 48.000265] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 48.005250] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 48.010154] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 48.015141] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 48.019879] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 48.024603] RIP: 0033:0x446549 [ 48.027761] RSP: 002b:00007f02eb37cdc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002b [ 48.035439] RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000446549 [ 48.042676] RDX: 000000002048bffc RSI: 0000000020b52000 RDI: 0000000000000003 [ 48.049913] RBP: 0000000000000000 R08: 00007f02eb37d700 R09: 00007f02eb37d700 [ 48.057150] R10: 00007f02eb37d700 R11: 0000000000000202 R12: 0000000000000000 [ 48.064389] R13: 00000000007efe7f R14: 00007f02eb37d9c0 R15: 0000000000000000 [ 48.072067] Dumping ftrace buffer: [ 48.075624] (ftrace buffer empty) [ 48.079303] Kernel Offset: disabled [ 48.082903] Rebooting in 86400 seconds..