INIT: Entering runlevel: 2 [[36minfo[39;49m] Using makefile-style concurrent boot in runlevel 2. [....] Starting enhanced syslogd: rsyslogd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting periodic command scheduler: cron[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. [....] Starting OpenBSD Secure Shell server: sshd[?25l[?1c7[1G[[32m ok [39;49m8[?25h[?0c. Debian GNU/Linux 7 syzkaller ttyS0 Warning: Permanently added 'ci-upstream-next-kasan-gce-2,10.128.15.201' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 51.035755] refcount_t: underflow; use-after-free. [ 51.040845] ------------[ cut here ]------------ [ 51.045824] WARNING: CPU: 0 PID: 3049 at lib/refcount.c:186 refcount_sub_and_test+0x167/0x1b0 [ 51.054555] Kernel panic - not syncing: panic_on_warn set ... [ 51.054555] [ 51.061915] CPU: 0 PID: 3049 Comm: syzkaller169030 Not tainted 4.13.0-rc6-next-20170825+ #9 [ 51.070399] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ 51.079861] Call Trace: [ 51.082442] dump_stack+0x194/0x257 [ 51.086062] ? arch_local_irq_restore+0x53/0x53 [ 51.090736] panic+0x1e4/0x41c [ 51.093939] ? refcount_error_report+0x214/0x214 [ 51.098681] ? show_regs_print_info+0x65/0x65 [ 51.103181] ? refcount_sub_and_test+0x167/0x1b0 [ 51.107918] __warn+0x1c4/0x1e0 [ 51.111180] ? refcount_sub_and_test+0x167/0x1b0 [ 51.115941] report_bug+0x211/0x2d0 [ 51.119560] fixup_bug+0x40/0x90 [ 51.122908] do_trap+0x260/0x390 [ 51.126269] do_error_trap+0x120/0x390 [ 51.130147] ? do_trap+0x390/0x390 [ 51.133668] ? refcount_sub_and_test+0x167/0x1b0 [ 51.138397] ? vprintk_emit+0x3ea/0x590 [ 51.142355] ? trace_hardirqs_off_thunk+0x1a/0x1c [ 51.147183] do_invalid_op+0x1b/0x20 [ 51.150875] invalid_op+0x18/0x20 [ 51.154304] RIP: 0010:refcount_sub_and_test+0x167/0x1b0 [ 51.159639] RSP: 0018:ffff8801cbc4e300 EFLAGS: 00010282 [ 51.164992] RAX: 0000000000000026 RBX: 0000000000000001 RCX: 0000000000000000 [ 51.172256] RDX: 0000000000000026 RSI: 1ffff10039789c20 RDI: ffffed0039789c54 [ 51.179503] RBP: ffff8801cbc4e390 R08: ffff8801cbc4d9f0 R09: 0000000000000000 [ 51.186749] R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10039789c61 [ 51.193999] R13: 00000000ffffff01 R14: 0000000000000100 R15: ffff8801cc048b24 [ 51.201541] ? refcount_inc+0x50/0x50 [ 51.205322] ? __sctp_outq_teardown+0xc7d/0x15a0 [ 51.210061] ? sctp_association_free+0x2d0/0x930 [ 51.214794] ? sctp_do_sm+0x28e7/0x6dd0 [ 51.218758] ? sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 51.223490] ? sctp_close+0x3c6/0x980 [ 51.227266] ? inet_release+0xed/0x1c0 [ 51.231138] sctp_wfree+0x183/0x620 [ 51.234758] ? __sctp_write_space+0x910/0x910 [ 51.239234] skb_release_head_state+0x124/0x200 [ 51.243892] skb_release_all+0x15/0x60 [ 51.247764] consume_skb+0x153/0x490 [ 51.251463] ? sctp_chunk_put+0x99/0x420 [ 51.255517] ? alloc_skb_with_frags+0x710/0x710 [ 51.260176] ? sctp_chunk_hold+0x20/0x20 [ 51.264224] ? refcount_sub_and_test+0x115/0x1b0 [ 51.268956] ? refcount_inc+0x50/0x50 [ 51.272730] ? mark_held_locks+0xb2/0x100 [ 51.277032] ? sctp_datamsg_put+0x456/0x560 [ 51.281332] sctp_chunk_put+0x29c/0x420 [ 51.285282] ? sctp_chunk_hold+0x20/0x20 [ 51.289325] ? sctp_transport_dst_confirm+0x50/0x50 [ 51.294341] sctp_chunk_free+0x53/0x60 [ 51.298205] __sctp_outq_teardown+0xc7d/0x15a0 [ 51.302761] ? inet6_release+0x50/0x70 [ 51.306629] ? sctp_inq_set_th_handler+0x1b0/0x1b0 [ 51.311542] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.316560] ? unwind_next_frame.part.6+0x1ae/0xc70 [ 51.321571] ? unwind_dump+0x4c0/0x4c0 [ 51.325456] ? unwind_dump+0x4c0/0x4c0 [ 51.329335] ? copy_trace+0x1d0/0x1d0 [ 51.333154] ? check_noncircular+0x20/0x20 [ 51.337398] ? check_noncircular+0x20/0x20 [ 51.341646] ? unwind_get_return_address+0x61/0xa0 [ 51.346595] ? __save_stack_trace+0x61/0xd0 [ 51.350958] ? check_noncircular+0x20/0x20 [ 51.355240] ? print_usage_bug+0x480/0x480 [ 51.359482] ? find_held_lock+0x39/0x1d0 [ 51.363558] ? lock_downgrade+0x990/0x990 [ 51.367739] ? sk_dst_check+0x560/0x560 [ 51.371721] ? rcu_read_lock_sched_held+0x108/0x120 [ 51.376741] ? lock_release+0xd70/0xd70 [ 51.380714] sctp_outq_free+0x15/0x20 [ 51.384510] sctp_association_free+0x2d0/0x930 [ 51.389139] ? sctp_asconf_queue_teardown+0x700/0x700 [ 51.394403] ? sock_def_wakeup+0x222/0x350 [ 51.398635] ? sk_dst_check+0x560/0x560 [ 51.402629] ? sctp_association_put+0x74/0x2f0 [ 51.407276] ? sctp_association_hold+0x20/0x20 [ 51.411857] ? __unwind_start+0x169/0x330 [ 51.416006] ? sctp_sm_lookup_event+0x95/0x3c0 [ 51.420615] sctp_do_sm+0x28e7/0x6dd0 [ 51.424430] ? sctp_do_8_2_transport_strike.isra.16+0x8a0/0x8a0 [ 51.430487] ? debug_check_no_locks_freed+0x3d0/0x3d0 [ 51.435672] ? print_usage_bug+0x480/0x480 [ 51.439945] ? print_usage_bug+0x480/0x480 [ 51.444199] ? find_held_lock+0x39/0x1d0 [ 51.448272] ? lock_downgrade+0x990/0x990 [ 51.452411] ? skb_dequeue+0x22/0x180 [ 51.456200] ? do_raw_spin_trylock+0x190/0x190 [ 51.460795] ? mark_held_locks+0xb2/0x100 [ 51.464939] ? trace_hardirqs_on+0xd/0x10 [ 51.469075] sctp_primitive_SHUTDOWN+0xa0/0xd0 [ 51.473638] sctp_close+0x3c6/0x980 [ 51.477264] ? sctp_apply_peer_addr_params+0xf30/0xf30 [ 51.482531] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.487564] ? trace_hardirqs_on+0xd/0x10 [ 51.491737] ? rcu_eqs_enter_common.constprop.73+0x270/0x270 [ 51.497529] ? ipv6_sock_ac_close+0x2e8/0x3e0 [ 51.502010] ? ipv6_sock_mc_close+0x148/0x1a0 [ 51.506487] ? ipv6_sock_ac_drop+0x580/0x580 [ 51.510869] ? ip_mc_drop_socket+0x1ce/0x230 [ 51.515258] ? __fsnotify_parent+0xb4/0x3a0 [ 51.519773] inet_release+0xed/0x1c0 [ 51.523508] inet6_release+0x50/0x70 [ 51.527217] sock_release+0x8d/0x1e0 [ 51.530924] ? sock_release+0x1e0/0x1e0 [ 51.534876] sock_close+0x16/0x20 [ 51.538309] __fput+0x333/0x7f0 [ 51.541582] ? fput+0x140/0x140 [ 51.544846] ? check_same_owner+0x320/0x320 [ 51.549150] ____fput+0x15/0x20 [ 51.552418] task_work_run+0x199/0x270 [ 51.556300] ? task_work_cancel+0x210/0x210 [ 51.560611] ? free_nsproxy+0x185/0x1f0 [ 51.564561] ? switch_task_namespaces+0xa2/0xc0 [ 51.569213] do_exit+0xa52/0x1b40 [ 51.572646] ? print_usage_bug+0x480/0x480 [ 51.576875] ? mm_update_next_owner+0x930/0x930 [ 51.581538] ? find_held_lock+0x39/0x1d0 [ 51.585593] ? check_noncircular+0x20/0x20 [ 51.589986] ? check_noncircular+0x20/0x20 [ 51.594208] ? lock_downgrade+0x990/0x990 [ 51.598348] ? reacquire_held_locks+0x205/0x3d0 [ 51.602993] ? check_noncircular+0x20/0x20 [ 51.607203] ? find_held_lock+0x39/0x1d0 [ 51.611271] ? lock_downgrade+0x990/0x990 [ 51.615392] ? lock_downgrade+0x990/0x990 [ 51.619523] ? find_held_lock+0x39/0x1d0 [ 51.623566] ? lock_downgrade+0x990/0x990 [ 51.627861] ? recalc_sigpending_tsk+0x117/0x150 [ 51.632590] ? recalc_sigpending+0x103/0x160 [ 51.636975] ? recalc_sigpending_tsk+0x150/0x150 [ 51.641709] ? get_signal+0x397/0x17e0 [ 51.645606] do_group_exit+0x149/0x400 [ 51.649488] ? __lock_is_held+0xbc/0x140 [ 51.653539] ? SyS_exit+0x30/0x30 [ 51.656969] ? _raw_spin_unlock_irq+0x27/0x70 [ 51.661453] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.666452] get_signal+0x7e8/0x17e0 [ 51.670168] ? ptrace_notify+0x130/0x130 [ 51.674203] ? __local_bh_enable_ip+0x9d/0x160 [ 51.678764] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.683762] ? release_sock+0x1d4/0x2a0 [ 51.687727] ? trace_hardirqs_on+0xd/0x10 [ 51.691869] ? __local_bh_enable_ip+0x9d/0x160 [ 51.696442] ? _raw_spin_unlock_bh+0x30/0x40 [ 51.700830] ? release_sock+0x1d4/0x2a0 [ 51.704789] ? trace_hardirqs_on+0xd/0x10 [ 51.708932] do_signal+0x94/0x1ee0 [ 51.712552] ? inet_sendmsg+0x11f/0x5e0 [ 51.716515] ? inet_sendmsg+0x126/0x5e0 [ 51.720483] ? __might_sleep+0x95/0x190 [ 51.724467] ? setup_sigcontext+0x7d0/0x7d0 [ 51.728784] ? selinux_socket_sendmsg+0x36/0x40 [ 51.733442] ? security_socket_sendmsg+0x89/0xb0 [ 51.738278] ? inet_recvmsg+0x5f0/0x5f0 [ 51.742235] ? sock_sendmsg+0x4f/0x110 [ 51.746099] ? fput+0xd2/0x140 [ 51.749271] ? SYSC_sendto+0x413/0x5a0 [ 51.753147] ? SYSC_connect+0x480/0x480 [ 51.757104] ? lock_downgrade+0x990/0x990 [ 51.761245] ? exit_to_usermode_loop+0x98/0x300 [ 51.765957] exit_to_usermode_loop+0x224/0x300 [ 51.770525] ? trace_event_raw_event_sys_exit+0x260/0x260 [ 51.776047] ? handle_mm_fault+0x4a2/0x860 [ 51.780263] ? down_read_trylock+0xdb/0x170 [ 51.784754] syscall_return_slowpath+0x42f/0x500 [ 51.789507] ? prepare_exit_to_usermode+0x2c0/0x2c0 [ 51.794515] ? entry_SYSCALL_64_fastpath+0x91/0xbe [ 51.799433] ? trace_hardirqs_on_caller+0x421/0x5c0 [ 51.804447] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 51.809208] entry_SYSCALL_64_fastpath+0xbc/0xbe [ 51.813957] RIP: 0033:0x445da9 [ 51.817142] RSP: 002b:00007f608d947db8 EFLAGS: 00000212 ORIG_RAX: 000000000000002c [ 51.824858] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000445da9 [ 51.832207] RDX: 0000000000000001 RSI: 0000000020018fff RDI: 0000000000000003 [ 51.839475] RBP: 0000000000000000 R08: 00000000206e4000 R09: 000000000000001c [ 51.846739] R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 [ 51.854093] R13: 00000000007efe8f R14: 00007f608d9489c0 R15: 0000000000000000 [ 51.862090] Dumping ftrace buffer: [ 51.865689] (ftrace buffer empty) [ 51.869376] Kernel Offset: disabled [ 51.873141] Rebooting in 86400 seconds..