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-2,10.128.0.52' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 26.250200] refcount_t: underflow; use-after-free. [ 26.251149] ------------[ cut here ]------------ [ 26.251812] WARNING: CPU: 1 PID: 2983 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 26.253182] Kernel panic - not syncing: panic_on_warn set ... [ 26.253182] [ 26.254153] CPU: 1 PID: 2983 Comm: syzkaller537054 Not tainted 4.14.0-rc5-next-20171018+ #36 [ 26.255276] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 26.256496] Call Trace: [ 26.256857] dump_stack+0x194/0x257 [ 26.257353] ? arch_local_irq_restore+0x53/0x53 [ 26.257984] ? vsnprintf+0x1ed/0x1900 [ 26.258514] panic+0x1e4/0x41c [ 26.258952] ? refcount_error_report+0x214/0x214 [ 26.259588] ? show_regs_print_info+0x65/0x65 [ 26.260195] ? retint_kernel+0x10/0x10 [ 26.260718] ? __warn+0x1a9/0x1e0 [ 26.261189] ? refcount_sub_and_test+0x167/0x1b0 [ 26.261825] __warn+0x1c4/0x1e0 [ 26.262288] ? refcount_sub_and_test+0x169/0x1b0 [ 26.262922] ? refcount_sub_and_test+0x167/0x1b0 [ 26.263559] report_bug+0x211/0x2d0 [ 26.264055] fixup_bug+0x40/0x90 [ 26.264512] do_trap+0x260/0x390 [ 26.264977] do_error_trap+0x120/0x390 [ 26.265499] ? vprintk_emit+0x49b/0x590 [ 26.266036] ? do_trap+0x390/0x390 [ 26.266516] ? refcount_sub_and_test+0x167/0x1b0 [ 26.267152] ? vprintk_emit+0x3ea/0x590 [ 26.267695] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 26.268358] do_invalid_op+0x1b/0x20 [ 26.268859] invalid_op+0x18/0x20 [ 26.269330] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 26.270039] RSP: 0018:ffff8801d23e6a38 EFLAGS: 00010282 [ 26.270751] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 26.277990] RDX: 0000000000000026 RSI: 1ffff1003a47cd07 RDI: ffffed003a47cd3b [ 26.285231] RBP: ffff8801d23e6ac8 R08: 0000000000000001 R09: 0000000000000000 [ 26.292474] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1003a47cd48 [ 26.299716] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801d1c84a3c [ 26.306998] ? refcount_sub_and_test+0x167/0x1b0 [ 26.311723] ? refcount_inc+0x50/0x50 [ 26.315495] ? sctp_outq_free+0x15/0x20 [ 26.319439] ? sctp_do_sm+0x271b/0x6a30 [ 26.323383] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 26.328106] ? sctp_close+0x3c6/0x980 [ 26.331875] ? inet_release+0xed/0x1c0 [ 26.335733] ? inet6_release+0x50/0x70 [ 26.339596] sctp_wfree+0x183/0x620 [ 26.343197] ? __sctp_write_space+0x910/0x910 [ 26.347661] skb_release_head_state+0x124/0x200 [ 26.352303] skb_release_all+0x15/0x60 [ 26.356160] consume_skb+0x153/0x490 [ 26.359840] ? sctp_chunk_put+0x99/0x420 [ 26.363872] ? alloc_skb_with_frags+0x750/0x750 [ 26.368506] ? sctp_chunk_hold+0x20/0x20 [ 26.372540] ? refcount_sub_and_test+0x115/0x1b0 [ 26.377265] ? refcount_inc+0x50/0x50 [ 26.381033] ? mark_held_locks+0xaf/0x100 [ 26.385152] ? sctp_datamsg_put+0x456/0x560 [ 26.389450] sctp_chunk_put+0x29c/0x420 [ 26.393396] ? sctp_chunk_hold+0x20/0x20 [ 26.397431] ? sctp_transport_dst_confirm+0x50/0x50 [ 26.402423] ? sctp_sched_fcfs_dequeue+0x198/0x290 [ 26.407324] ? sctp_sched_dequeue_common+0x5d0/0x5d0 [ 26.412400] sctp_chunk_free+0x53/0x60 [ 26.416256] __sctp_outq_teardown+0xa5b/0x1230 [ 26.420818] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 26.425719] ? __kernel_text_address+0xd/0x40 [ 26.430185] ? unwind_get_return_address+0x61/0xa0 [ 26.435083] ? __save_stack_trace+0x7e/0xd0 [ 26.439380] ? add_lock_to_list.isra.32+0x292/0x39b [ 26.444375] ? check_noncircular+0x20/0x20 [ 26.448583] ? print_irqtrace_events+0x270/0x270 [ 26.453321] ? lock_acquire+0x1d5/0x580 [ 26.457261] ? lock_acquire+0x1d5/0x580 [ 26.461205] ? lock_timer_base+0x1a3/0x2b0 [ 26.465414] ? find_held_lock+0x35/0x1d0 [ 26.469454] ? sock_def_wakeup+0x1f9/0x350 [ 26.473660] ? lock_downgrade+0x990/0x990 [ 26.477780] ? lock_release+0xa40/0xa40 [ 26.481729] sctp_outq_free+0x15/0x20 [ 26.485505] sctp_association_free+0x2d0/0x930 [ 26.490061] ? sctp_asconf_queue_teardown+0x700/0x700 [ 26.495220] ? sock_def_wakeup+0x222/0x350 [ 26.499426] ? sk_dst_check+0x560/0x560 [ 26.503369] ? sctp_association_put+0x74/0x2f0 [ 26.507921] ? sctp_association_hold+0x20/0x20 [ 26.512484] sctp_do_sm+0x271b/0x6a30 [ 26.516266] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 26.522297] ? __free_insn_slot+0x5c0/0x5c0 [ 26.526591] ? print_irqtrace_events+0x270/0x270 [ 26.531321] ? print_irqtrace_events+0x270/0x270 [ 26.536061] ? find_held_lock+0x35/0x1d0 [ 26.540100] ? skb_dequeue+0x12a/0x180 [ 26.543960] ? lock_downgrade+0x990/0x990 [ 26.548082] ? do_raw_spin_trylock+0x190/0x190 [ 26.552636] ? mark_held_locks+0xaf/0x100 [ 26.556764] ? trace_hardirqs_on+0xd/0x10 [ 26.560889] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 26.565446] sctp_close+0x3c6/0x980 [ 26.569052] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 26.574300] ? unwind_get_return_address+0x61/0xa0 [ 26.579201] ? __save_stack_trace+0x7e/0xd0 [ 26.583496] ? check_noncircular+0x20/0x20 [ 26.587703] ? check_noncircular+0x20/0x20 [ 26.591919] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 26.596386] ? ipv6_sock_mc_close+0x148/0x1a0 [ 26.600854] ? ip_mc_drop_socket+0x1ce/0x230 [ 26.605233] ? __fsnotify_parent+0xb4/0x3a0 [ 26.609529] inet_release+0xed/0x1c0 [ 26.613218] inet6_release+0x50/0x70 [ 26.616907] sock_release+0x8d/0x1e0 [ 26.620593] ? sock_release+0x1e0/0x1e0 [ 26.624538] sock_close+0x16/0x20 [ 26.627963] __fput+0x327/0x7e0 [ 26.631220] ? fput+0x140/0x140 [ 26.634476] ? _raw_spin_unlock_irq+0x27/0x70 [ 26.638949] ____fput+0x15/0x20 [ 26.642198] task_work_run+0x199/0x270 [ 26.646061] ? task_work_cancel+0x210/0x210 [ 26.650354] ? _raw_spin_unlock+0x22/0x30 [ 26.654474] ? switch_task_namespaces+0x87/0xc0 [ 26.659120] do_exit+0x9b5/0x1ad0 [ 26.662542] ? __fd_install+0x2da/0x6a0 [ 26.666493] ? mm_update_next_owner+0x930/0x930 [ 26.671138] ? __lock_is_held+0xb6/0x140 [ 26.675183] ? __fd_install+0x2f7/0x6a0 [ 26.679133] ? get_unused_fd_flags+0x190/0x190 [ 26.683694] ? __might_sleep+0x95/0x190 [ 26.687643] ? kasan_check_read+0x11/0x20 [ 26.691761] ? _copy_to_user+0xa2/0xc0 [ 26.695624] ? fd_install+0x4d/0x60 [ 26.699224] ? SYSC_accept4+0x4ec/0x850 [ 26.703169] ? __release_sock+0x360/0x360 [ 26.707289] ? kernel_accept+0x2f0/0x2f0 [ 26.711324] ? sctp_inet_listen+0x141/0x850 [ 26.715619] ? sctp_transport_get_idx+0x70/0x70 [ 26.720261] ? selinux_socket_listen+0x36/0x40 [ 26.724813] ? security_socket_listen+0x81/0xb0 [ 26.729454] do_group_exit+0x149/0x400 [ 26.733310] ? SyS_bind+0x30/0x30 [ 26.736734] ? SyS_exit+0x30/0x30 [ 26.740161] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 26.745151] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 26.749883] SyS_exit_group+0x1d/0x20 [ 26.753655] entry_SYSCALL_64_fastpath+0x1f/0xbe [ 26.758379] RIP: 0033:0x43e9d8 [ 26.761539] RSP: 002b:00007ffc3cb706b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 [ 26.769217] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043e9d8 [ 26.776455] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 [ 26.783696] RBP: 0000000000000082 R08: 00000000000000e7 R09: ffffffffffffffd0 [ 26.790936] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401700 [ 26.798176] R13: 0000000000401790 R14: 0000000000000000 R15: 0000000000000000 [ 26.805577] Dumping ftrace buffer: [ 26.809134] (ftrace buffer empty) [ 26.812817] Kernel Offset: disabled [ 26.816419] Rebooting in 86400 seconds..