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-386-4,10.128.0.25' (ECDSA) to the list of known hosts.
net.ipv6.conf.syz0.accept_dad = 0
net.ipv6.conf.syz0.router_solicitations = 0
executing program
syzkaller login: [   44.610295] ==================================================================
[   44.617762] BUG: KASAN: use-after-free in detach_if_pending+0x557/0x610
[   44.624487] Write of size 8 at addr ffff8801ce16b740 by task syzkaller991817/2987
[   44.632079] 
[   44.633683] CPU: 0 PID: 2987 Comm: syzkaller991817 Not tainted 4.14.0-rc2+ #20
[   44.641012] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   44.650345] Call Trace:
[   44.652910]  dump_stack+0x194/0x257
[   44.656515]  ? arch_local_irq_restore+0x53/0x53
[   44.661168]  ? show_regs_print_info+0x65/0x65
[   44.665639]  ? lock_timer_base+0x1a3/0x2b0
[   44.669846]  ? detach_if_pending+0x557/0x610
[   44.674228]  print_address_description+0x73/0x250
[   44.679041]  ? detach_if_pending+0x557/0x610
[   44.683429]  kasan_report+0x25b/0x340
[   44.687204]  __asan_report_store8_noabort+0x17/0x20
[   44.692191]  detach_if_pending+0x557/0x610
[   44.696401]  ? trace_raw_output_tick_stop+0x130/0x130
[   44.701561]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   44.706198]  ? lock_timer_base+0x1a3/0x2b0
[   44.710404]  ? lock_timer_base+0x1eb/0x2b0
[   44.714614]  ? __internal_add_timer+0x2d0/0x2d0
[   44.719258]  ? trace_hardirqs_on+0xd/0x10
[   44.723384]  try_to_del_timer_sync+0xa2/0x120
[   44.727849]  ? del_timer+0x130/0x130
[   44.731534]  ? del_timer_sync+0xeb/0x240
[   44.735571]  del_timer_sync+0x18a/0x240
[   44.739519]  tun_free_netdev+0x105/0x1b0
[   44.743551]  ? tun_xdp+0x410/0x410
[   44.747060]  ? cpumask_next+0x24/0x30
[   44.750831]  ? netdev_refcnt_read+0xed/0x150
[   44.755212]  ? tun_xdp+0x410/0x410
[   44.758723]  netdev_run_todo+0x870/0xca0
[   44.762754]  ? do_group_exit+0x149/0x400
[   44.766792]  ? register_netdev+0x30/0x30
[   44.770829]  ? lock_downgrade+0x990/0x990
[   44.774946]  ? trace_hardirqs_on+0xd/0x10
[   44.779083]  ? refcount_sub_and_test+0x115/0x1b0
[   44.783810]  ? refcount_inc+0x50/0x50
[   44.787584]  ? refcount_inc+0x50/0x50
[   44.791360]  ? sk_destruct+0x4c/0x80
[   44.795044]  ? __sk_free+0x5c/0x230
[   44.798641]  ? sk_free+0x2f/0x40
[   44.801977]  ? __tun_detach+0x176/0x1390
[   44.806019]  ? tun_attach+0xf90/0xf90
[   44.809793]  ? do_raw_spin_trylock+0x190/0x190
[   44.814351]  ? locks_remove_file+0x3fa/0x5a0
[   44.818732]  ? fcntl_setlk+0x10d0/0x10d0
[   44.822767]  ? __fsnotify_parent+0xb4/0x3a0
[   44.827061]  ? fsnotify+0x1af0/0x1af0
[   44.830836]  ? __tun_detach+0x1390/0x1390
[   44.834952]  ? __tun_detach+0x1390/0x1390
[   44.839072]  rtnl_unlock+0xe/0x10
[   44.842493]  tun_chr_close+0x49/0x60
[   44.846178]  __fput+0x333/0x7f0
[   44.849435]  ? fput+0x140/0x140
[   44.852690]  ? check_same_owner+0x320/0x320
[   44.856980]  ? _raw_spin_unlock_irq+0x27/0x70
[   44.861453]  ____fput+0x15/0x20
[   44.864705]  task_work_run+0x199/0x270
[   44.868566]  ? task_work_cancel+0x210/0x210
[   44.872860]  ? _raw_spin_unlock+0x22/0x30
[   44.876980]  ? switch_task_namespaces+0x87/0xc0
[   44.881624]  do_exit+0x9d2/0x1af0
[   44.885054]  ? mm_update_next_owner+0x930/0x930
[   44.889694]  ? lock_acquire+0x1d5/0x580
[   44.893641]  ? __handle_mm_fault+0xf07/0x39c0
[   44.898114]  ? lock_release+0xd70/0xd70
[   44.902057]  ? check_noncircular+0x20/0x20
[   44.906263]  ? kvfree+0x3b/0x60
[   44.909520]  ? rtnl_unlock+0xe/0x10
[   44.913118]  ? check_noncircular+0x20/0x20
[   44.917331]  ? __handle_mm_fault+0x587/0x39c0
[   44.921801]  ? __pmd_alloc+0x4e0/0x4e0
[   44.925668]  ? find_held_lock+0x39/0x1d0
[   44.929709]  ? lock_downgrade+0x990/0x990
[   44.933854]  do_group_exit+0x149/0x400
[   44.937707]  ? __handle_mm_fault+0x39c0/0x39c0
[   44.942258]  ? vmacache_find+0x5f/0x280
[   44.946206]  ? SyS_exit+0x30/0x30
[   44.949638]  ? do_fast_syscall_32+0x158/0xf05
[   44.954105]  ? do_group_exit+0x400/0x400
[   44.958135]  SyS_exit_group+0x1d/0x20
[   44.961906]  do_fast_syscall_32+0x3f2/0xf05
[   44.966204]  ? do_int80_syscall_32+0x940/0x940
[   44.970759]  ? kasan_check_read+0x11/0x20
[   44.974878]  ? syscall_return_slowpath+0x510/0x510
[   44.979778]  ? SyS_rt_sigaction+0x94/0x1b0
[   44.983987]  ? lockdep_sys_exit+0x47/0xf0
[   44.988106]  ? retint_user+0x18/0x20
[   44.991797]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   44.996616]  entry_SYSENTER_compat+0x51/0x60
[   45.000992] RIP: 0023:0xf7f81c79
[   45.004327] RSP: 002b:00000000ffcd22ac EFLAGS: 00000292 ORIG_RAX: 00000000000000fc
[   45.012008] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080f2298
[   45.019246] RDX: 0000000000000000 RSI: 00000000080db958 RDI: 00000000080f22a0
[   45.026486] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[   45.033725] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   45.040964] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   45.048220] 
[   45.049818] Allocated by task 2987:
[   45.053422]  save_stack_trace+0x16/0x20
[   45.057367]  save_stack+0x43/0xd0
[   45.060788]  kasan_kmalloc+0xad/0xe0
[   45.064469]  __kmalloc_node+0x47/0x70
[   45.068239]  kvmalloc_node+0x64/0xd0
[   45.071923]  alloc_netdev_mqs+0x16e/0xed0
[   45.076040]  __tun_chr_ioctl+0x12be/0x3d20
[   45.080243]  tun_chr_compat_ioctl+0x29/0x30
[   45.084534]  compat_SyS_ioctl+0x1d7/0x3290
[   45.088736]  do_fast_syscall_32+0x3f2/0xf05
[   45.093026]  entry_SYSENTER_compat+0x51/0x60
[   45.097401] 
[   45.098996] Freed by task 2987:
[   45.102244]  save_stack_trace+0x16/0x20
[   45.106185]  save_stack+0x43/0xd0
[   45.109623]  kasan_slab_free+0x71/0xc0
[   45.113478]  kfree+0xca/0x250
[   45.116552]  kvfree+0x36/0x60
[   45.119625]  free_netdev+0x2cf/0x360
[   45.123306]  __tun_chr_ioctl+0x2cf6/0x3d20
[   45.127509]  tun_chr_compat_ioctl+0x29/0x30
[   45.131799]  compat_SyS_ioctl+0x1d7/0x3290
[   45.136002]  do_fast_syscall_32+0x3f2/0xf05
[   45.140293]  entry_SYSENTER_compat+0x51/0x60
[   45.144677] 
[   45.146277] The buggy address belongs to the object at ffff8801ce168340
[   45.146277]  which belongs to the cache kmalloc-16384 of size 16384
[   45.159247] The buggy address is located 13312 bytes inside of
[   45.159247]  16384-byte region [ffff8801ce168340, ffff8801ce16c340)
[   45.171436] The buggy address belongs to the page:
[   45.176335] page:ffffea0007385a00 count:1 mapcount:0 mapping:ffff8801ce168340 index:0x0 compound_mapcount: 0
[   45.186290] flags: 0x200000000008100(slab|head)
[   45.190930] raw: 0200000000008100 ffff8801ce168340 0000000000000000 0000000100000001
[   45.198780] raw: ffffea000738a420 ffff8801dac01c50 ffff8801dac02200 0000000000000000
[   45.206626] page dumped because: kasan: bad access detected
[   45.212302] 
[   45.213901] Memory state around the buggy address:
[   45.218797]  ffff8801ce16b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   45.226125]  ffff8801ce16b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   45.233454] >ffff8801ce16b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   45.240780]                                            ^
[   45.246196]  ffff8801ce16b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   45.253524]  ffff8801ce16b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   45.260848] ==================================================================
[   45.268172] Disabling lock debugging due to kernel taint
[   45.273585] Kernel panic - not syncing: panic_on_warn set ...
[   45.273585] 
[   45.280918] CPU: 0 PID: 2987 Comm: syzkaller991817 Tainted: G    B           4.14.0-rc2+ #20
[   45.289454] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   45.298771] Call Trace:
[   45.301323]  dump_stack+0x194/0x257
[   45.304915]  ? arch_local_irq_restore+0x53/0x53
[   45.309551]  ? vprintk_default+0x28/0x30
[   45.313581]  ? detach_if_pending+0x4d0/0x610
[   45.317957]  panic+0x1e4/0x417
[   45.321113]  ? __warn+0x1d9/0x1d9
[   45.324538]  ? detach_if_pending+0x557/0x610
[   45.328908]  kasan_end_report+0x50/0x50
[   45.332846]  kasan_report+0x144/0x340
[   45.336613]  __asan_report_store8_noabort+0x17/0x20
[   45.341593]  detach_if_pending+0x557/0x610
[   45.345793]  ? trace_raw_output_tick_stop+0x130/0x130
[   45.350945]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   45.355577]  ? lock_timer_base+0x1a3/0x2b0
[   45.359776]  ? lock_timer_base+0x1eb/0x2b0
[   45.363974]  ? __internal_add_timer+0x2d0/0x2d0
[   45.368607]  ? trace_hardirqs_on+0xd/0x10
[   45.372721]  try_to_del_timer_sync+0xa2/0x120
[   45.377178]  ? del_timer+0x130/0x130
[   45.380855]  ? del_timer_sync+0xeb/0x240
[   45.384894]  del_timer_sync+0x18a/0x240
[   45.388834]  tun_free_netdev+0x105/0x1b0
[   45.392859]  ? tun_xdp+0x410/0x410
[   45.396363]  ? cpumask_next+0x24/0x30
[   45.400138]  ? netdev_refcnt_read+0xed/0x150
[   45.404511]  ? tun_xdp+0x410/0x410
[   45.408013]  netdev_run_todo+0x870/0xca0
[   45.412038]  ? do_group_exit+0x149/0x400
[   45.416066]  ? register_netdev+0x30/0x30
[   45.420092]  ? lock_downgrade+0x990/0x990
[   45.424203]  ? trace_hardirqs_on+0xd/0x10
[   45.428328]  ? refcount_sub_and_test+0x115/0x1b0
[   45.433048]  ? refcount_inc+0x50/0x50
[   45.436813]  ? refcount_inc+0x50/0x50
[   45.440578]  ? sk_destruct+0x4c/0x80
[   45.444253]  ? __sk_free+0x5c/0x230
[   45.447843]  ? sk_free+0x2f/0x40
[   45.451171]  ? __tun_detach+0x176/0x1390
[   45.455202]  ? tun_attach+0xf90/0xf90
[   45.458969]  ? do_raw_spin_trylock+0x190/0x190
[   45.463516]  ? locks_remove_file+0x3fa/0x5a0
[   45.467889]  ? fcntl_setlk+0x10d0/0x10d0
[   45.471916]  ? __fsnotify_parent+0xb4/0x3a0
[   45.476201]  ? fsnotify+0x1af0/0x1af0
[   45.479969]  ? __tun_detach+0x1390/0x1390
[   45.484079]  ? __tun_detach+0x1390/0x1390
[   45.488190]  rtnl_unlock+0xe/0x10
[   45.491617]  tun_chr_close+0x49/0x60
[   45.495295]  __fput+0x333/0x7f0
[   45.498543]  ? fput+0x140/0x140
[   45.501786]  ? check_same_owner+0x320/0x320
[   45.506071]  ? _raw_spin_unlock_irq+0x27/0x70
[   45.510532]  ____fput+0x15/0x20
[   45.513776]  task_work_run+0x199/0x270
[   45.517627]  ? task_work_cancel+0x210/0x210
[   45.521913]  ? _raw_spin_unlock+0x22/0x30
[   45.526024]  ? switch_task_namespaces+0x87/0xc0
[   45.530657]  do_exit+0x9d2/0x1af0
[   45.534077]  ? mm_update_next_owner+0x930/0x930
[   45.538710]  ? lock_acquire+0x1d5/0x580
[   45.542647]  ? __handle_mm_fault+0xf07/0x39c0
[   45.547110]  ? lock_release+0xd70/0xd70
[   45.551047]  ? check_noncircular+0x20/0x20
[   45.555263]  ? kvfree+0x3b/0x60
[   45.558508]  ? rtnl_unlock+0xe/0x10
[   45.562099]  ? check_noncircular+0x20/0x20
[   45.566303]  ? __handle_mm_fault+0x587/0x39c0
[   45.570763]  ? __pmd_alloc+0x4e0/0x4e0
[   45.574619]  ? find_held_lock+0x39/0x1d0
[   45.578650]  ? lock_downgrade+0x990/0x990
[   45.582775]  do_group_exit+0x149/0x400
[   45.586627]  ? __handle_mm_fault+0x39c0/0x39c0
[   45.591176]  ? vmacache_find+0x5f/0x280
[   45.595113]  ? SyS_exit+0x30/0x30
[   45.598534]  ? do_fast_syscall_32+0x158/0xf05
[   45.602992]  ? do_group_exit+0x400/0x400
[   45.607017]  SyS_exit_group+0x1d/0x20