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-386-0,10.128.0.4' (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: [   41.353293] ==================================================================
[   41.360746] BUG: KASAN: use-after-free in detach_if_pending+0x557/0x610
[   41.367471] Write of size 8 at addr ffff8801ce20b740 by task syzkaller172162/2986
[   41.375059] 
[   41.376660] CPU: 0 PID: 2986 Comm: syzkaller172162 Not tainted 4.14.0-rc2+ #20
[   41.383999] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   41.393324] Call Trace:
[   41.395886]  dump_stack+0x194/0x257
[   41.399486]  ? arch_local_irq_restore+0x53/0x53
[   41.404127]  ? show_regs_print_info+0x65/0x65
[   41.408597]  ? lock_timer_base+0x1a3/0x2b0
[   41.412804]  ? detach_if_pending+0x557/0x610
[   41.417191]  print_address_description+0x73/0x250
[   41.422006]  ? detach_if_pending+0x557/0x610
[   41.426387]  kasan_report+0x25b/0x340
[   41.430162]  __asan_report_store8_noabort+0x17/0x20
[   41.435151]  detach_if_pending+0x557/0x610
[   41.439363]  ? trace_raw_output_tick_stop+0x130/0x130
[   41.444527]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   41.449164]  ? lock_timer_base+0x1a3/0x2b0
[   41.453372]  ? lock_timer_base+0x1eb/0x2b0
[   41.457582]  ? __internal_add_timer+0x2d0/0x2d0
[   41.462226]  ? trace_hardirqs_on+0xd/0x10
[   41.466353]  try_to_del_timer_sync+0xa2/0x120
[   41.470818]  ? del_timer+0x130/0x130
[   41.474504]  ? del_timer_sync+0xeb/0x240
[   41.478544]  del_timer_sync+0x18a/0x240
[   41.482493]  tun_free_netdev+0x105/0x1b0
[   41.486525]  ? tun_xdp+0x410/0x410
[   41.490034]  ? cpumask_next+0x24/0x30
[   41.493817]  ? netdev_refcnt_read+0xed/0x150
[   41.498201]  ? tun_xdp+0x410/0x410
[   41.501712]  netdev_run_todo+0x870/0xca0
[   41.505744]  ? do_group_exit+0x149/0x400
[   41.509779]  ? register_netdev+0x30/0x30
[   41.513814]  ? lock_downgrade+0x990/0x990
[   41.517935]  ? trace_hardirqs_on+0xd/0x10
[   41.522072]  ? refcount_sub_and_test+0x115/0x1b0
[   41.526797]  ? refcount_inc+0x50/0x50
[   41.530572]  ? refcount_inc+0x50/0x50
[   41.534349]  ? sk_destruct+0x4c/0x80
[   41.538033]  ? __sk_free+0x5c/0x230
[   41.541631]  ? sk_free+0x2f/0x40
[   41.544971]  ? __tun_detach+0x176/0x1390
[   41.549014]  ? tun_attach+0xf90/0xf90
[   41.552787]  ? do_raw_spin_trylock+0x190/0x190
[   41.557343]  ? locks_remove_file+0x3fa/0x5a0
[   41.561728]  ? fcntl_setlk+0x10d0/0x10d0
[   41.565761]  ? __fsnotify_parent+0xb4/0x3a0
[   41.570055]  ? fsnotify+0x1af0/0x1af0
[   41.573828]  ? __tun_detach+0x1390/0x1390
[   41.577947]  ? __tun_detach+0x1390/0x1390
[   41.582066]  rtnl_unlock+0xe/0x10
[   41.585486]  tun_chr_close+0x49/0x60
[   41.589171]  __fput+0x333/0x7f0
[   41.592429]  ? fput+0x140/0x140
[   41.595681]  ? check_same_owner+0x320/0x320
[   41.599970]  ? _raw_spin_unlock_irq+0x27/0x70
[   41.604444]  ____fput+0x15/0x20
[   41.607695]  task_work_run+0x199/0x270
[   41.611557]  ? task_work_cancel+0x210/0x210
[   41.615851]  ? _raw_spin_unlock+0x22/0x30
[   41.619969]  ? switch_task_namespaces+0x87/0xc0
[   41.624611]  do_exit+0x9d2/0x1af0
[   41.628042]  ? mm_update_next_owner+0x930/0x930
[   41.632682]  ? lock_acquire+0x1d5/0x580
[   41.636627]  ? __handle_mm_fault+0xf07/0x39c0
[   41.641109]  ? lock_release+0xd70/0xd70
[   41.645054]  ? check_noncircular+0x20/0x20
[   41.649264]  ? kvfree+0x3b/0x60
[   41.652521]  ? rtnl_unlock+0xe/0x10
[   41.656118]  ? check_noncircular+0x20/0x20
[   41.660327]  ? __handle_mm_fault+0x587/0x39c0
[   41.664802]  ? __pmd_alloc+0x4e0/0x4e0
[   41.668669]  ? find_held_lock+0x39/0x1d0
[   41.672710]  ? lock_downgrade+0x990/0x990
[   41.676855]  do_group_exit+0x149/0x400
[   41.680709]  ? __handle_mm_fault+0x39c0/0x39c0
[   41.685259]  ? vmacache_find+0x5f/0x280
[   41.689203]  ? SyS_exit+0x30/0x30
[   41.692631]  ? do_fast_syscall_32+0x158/0xf05
[   41.697096]  ? do_group_exit+0x400/0x400
[   41.701127]  SyS_exit_group+0x1d/0x20
[   41.704899]  do_fast_syscall_32+0x3f2/0xf05
[   41.709196]  ? do_int80_syscall_32+0x940/0x940
[   41.713749]  ? kasan_check_read+0x11/0x20
[   41.717868]  ? syscall_return_slowpath+0x510/0x510
[   41.722769]  ? SyS_rt_sigaction+0x94/0x1b0
[   41.726977]  ? lockdep_sys_exit+0x47/0xf0
[   41.731093]  ? retint_user+0x18/0x20
[   41.734782]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[   41.739602]  entry_SYSENTER_compat+0x51/0x60
[   41.743991] RIP: 0023:0xf7f17c79
[   41.747326] RSP: 002b:00000000ffe57e6c EFLAGS: 00000296 ORIG_RAX: 00000000000000fc
[   41.755009] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080f1298
[   41.762251] RDX: 0000000000000000 RSI: 00000000080dae18 RDI: 00000000080f12a0
[   41.769491] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[   41.776730] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   41.783978] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   41.791238] 
[   41.792837] Allocated by task 2986:
[   41.796437]  save_stack_trace+0x16/0x20
[   41.800383]  save_stack+0x43/0xd0
[   41.803803]  kasan_kmalloc+0xad/0xe0
[   41.807484]  __kmalloc_node+0x47/0x70
[   41.811254]  kvmalloc_node+0x64/0xd0
[   41.814941]  alloc_netdev_mqs+0x16e/0xed0
[   41.819067]  __tun_chr_ioctl+0x12be/0x3d20
[   41.823271]  tun_chr_compat_ioctl+0x29/0x30
[   41.827562]  compat_SyS_ioctl+0x1d7/0x3290
[   41.831767]  do_fast_syscall_32+0x3f2/0xf05
[   41.836061]  entry_SYSENTER_compat+0x51/0x60
[   41.840434] 
[   41.842031] Freed by task 2986:
[   41.845279]  save_stack_trace+0x16/0x20
[   41.849220]  save_stack+0x43/0xd0
[   41.852652]  kasan_slab_free+0x71/0xc0
[   41.856509]  kfree+0xca/0x250
[   41.859585]  kvfree+0x36/0x60
[   41.862659]  free_netdev+0x2cf/0x360
[   41.866343]  __tun_chr_ioctl+0x2cf6/0x3d20
[   41.870545]  tun_chr_compat_ioctl+0x29/0x30
[   41.874837]  compat_SyS_ioctl+0x1d7/0x3290
[   41.879040]  do_fast_syscall_32+0x3f2/0xf05
[   41.883347]  entry_SYSENTER_compat+0x51/0x60
[   41.887722] 
[   41.889320] The buggy address belongs to the object at ffff8801ce208340
[   41.889320]  which belongs to the cache kmalloc-16384 of size 16384
[   41.902293] The buggy address is located 13312 bytes inside of
[   41.902293]  16384-byte region [ffff8801ce208340, ffff8801ce20c340)
[   41.914480] The buggy address belongs to the page:
[   41.919380] page:ffffea0007388200 count:1 mapcount:0 mapping:ffff8801ce208340 index:0x0 compound_mapcount: 0
[   41.929324] flags: 0x200000000008100(slab|head)
[   41.933967] raw: 0200000000008100 ffff8801ce208340 0000000000000000 0000000100000001
[   41.941818] raw: ffffea000741e420 ffff8801dac01c50 ffff8801dac02200 0000000000000000
[   41.949797] page dumped because: kasan: bad access detected
[   41.955478] 
[   41.957075] Memory state around the buggy address:
[   41.961973]  ffff8801ce20b600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   41.969301]  ffff8801ce20b680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   41.976631] >ffff8801ce20b700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   41.983959]                                            ^
[   41.989377]  ffff8801ce20b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   41.996705]  ffff8801ce20b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[   42.004031] ==================================================================
[   42.011357] Disabling lock debugging due to kernel taint
[   42.016770] Kernel panic - not syncing: panic_on_warn set ...
[   42.016770] 
[   42.024097] CPU: 0 PID: 2986 Comm: syzkaller172162 Tainted: G    B           4.14.0-rc2+ #20
[   42.032634] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[   42.041950] Call Trace:
[   42.044511]  dump_stack+0x194/0x257
[   42.048105]  ? arch_local_irq_restore+0x53/0x53
[   42.052740]  ? vprintk_default+0x28/0x30
[   42.056768]  ? detach_if_pending+0x4d0/0x610
[   42.061145]  panic+0x1e4/0x417
[   42.064303]  ? __warn+0x1d9/0x1d9
[   42.067727]  ? detach_if_pending+0x557/0x610
[   42.072100]  kasan_end_report+0x50/0x50
[   42.076038]  kasan_report+0x144/0x340
[   42.079803]  __asan_report_store8_noabort+0x17/0x20
[   42.084781]  detach_if_pending+0x557/0x610
[   42.088980]  ? trace_raw_output_tick_stop+0x130/0x130
[   42.094135]  ? _raw_spin_lock_irqsave+0x9e/0xc0
[   42.098766]  ? lock_timer_base+0x1a3/0x2b0
[   42.102964]  ? lock_timer_base+0x1eb/0x2b0
[   42.107164]  ? __internal_add_timer+0x2d0/0x2d0
[   42.111802]  ? trace_hardirqs_on+0xd/0x10
[   42.115920]  try_to_del_timer_sync+0xa2/0x120
[   42.120379]  ? del_timer+0x130/0x130
[   42.124058]  ? del_timer_sync+0xeb/0x240
[   42.128087]  del_timer_sync+0x18a/0x240
[   42.132029]  tun_free_netdev+0x105/0x1b0
[   42.136053]  ? tun_xdp+0x410/0x410
[   42.139558]  ? cpumask_next+0x24/0x30
[   42.143329]  ? netdev_refcnt_read+0xed/0x150
[   42.147705]  ? tun_xdp+0x410/0x410
[   42.151212]  netdev_run_todo+0x870/0xca0
[   42.155237]  ? do_group_exit+0x149/0x400
[   42.159265]  ? register_netdev+0x30/0x30
[   42.163294]  ? lock_downgrade+0x990/0x990
[   42.167410]  ? trace_hardirqs_on+0xd/0x10
[   42.171534]  ? refcount_sub_and_test+0x115/0x1b0
[   42.176255]  ? refcount_inc+0x50/0x50
[   42.180021]  ? refcount_inc+0x50/0x50
[   42.183790]  ? sk_destruct+0x4c/0x80
[   42.187467]  ? __sk_free+0x5c/0x230
[   42.191060]  ? sk_free+0x2f/0x40
[   42.194392]  ? __tun_detach+0x176/0x1390
[   42.198422]  ? tun_attach+0xf90/0xf90
[   42.202190]  ? do_raw_spin_trylock+0x190/0x190
[   42.206741]  ? locks_remove_file+0x3fa/0x5a0
[   42.211115]  ? fcntl_setlk+0x10d0/0x10d0
[   42.215142]  ? __fsnotify_parent+0xb4/0x3a0
[   42.219431]  ? fsnotify+0x1af0/0x1af0
[   42.223196]  ? __tun_detach+0x1390/0x1390
[   42.227307]  ? __tun_detach+0x1390/0x1390
[   42.231422]  rtnl_unlock+0xe/0x10
[   42.234840]  tun_chr_close+0x49/0x60
[   42.238522]  __fput+0x333/0x7f0
[   42.241769]  ? fput+0x140/0x140
[   42.245015]  ? check_same_owner+0x320/0x320
[   42.249301]  ? _raw_spin_unlock_irq+0x27/0x70
[   42.253761]  ____fput+0x15/0x20
[   42.257007]  task_work_run+0x199/0x270
[   42.260858]  ? task_work_cancel+0x210/0x210
[   42.265145]  ? _raw_spin_unlock+0x22/0x30
[   42.269260]  ? switch_task_namespaces+0x87/0xc0
[   42.273898]  do_exit+0x9d2/0x1af0
[   42.277319]  ? mm_update_next_owner+0x930/0x930
[   42.281951]  ? lock_acquire+0x1d5/0x580
[   42.285889]  ? __handle_mm_fault+0xf07/0x39c0
[   42.290355]  ? lock_release+0xd70/0xd70
[   42.294292]  ? check_noncircular+0x20/0x20
[   42.298494]  ? kvfree+0x3b/0x60
[   42.301743]  ? rtnl_unlock+0xe/0x10
[   42.305335]  ? check_noncircular+0x20/0x20
[   42.309534]  ? __handle_mm_fault+0x587/0x39c0
[   42.313996]  ? __pmd_alloc+0x4e0/0x4e0
[   42.317854]  ? find_held_lock+0x39/0x1d0
[   42.321886]  ? lock_downgrade+0x990/0x990
[   42.326013]  do_group_exit+0x149/0x400
[   42.329863]  ? __handle_mm_fault+0x39c0/0x39c0
[   42.334410]  ? vmacache_find+0x5f/0x280
[   42.338349]  ? SyS_exit+0x30/0x30
[   42.341770]  ? do_fast_syscall_32+0x158/0xf05
[   42.346230]  ? do_group_exit+0x400/0x400
[   42.350255]  SyS_exit_group+0x1d/0x20