==================================================================
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x2f9/0x340 fs/ext4/dir.c:68
Read of size 2 at addr ffff88809ddd7002 by task syz-executor.4/18144

CPU: 1 PID: 18144 Comm: syz-executor.4 Not tainted 4.14.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 __ext4_check_dir_entry+0x2f9/0x340 fs/ext4/dir.c:68
 ext4_readdir+0x822/0x27f0 fs/ext4/dir.c:240
 iterate_dir+0x1a0/0x5e0 fs/readdir.c:52
 SYSC_getdents64 fs/readdir.c:355 [inline]
 SyS_getdents64+0x130/0x240 fs/readdir.c:336
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c829
RSP: 002b:00007fc81b35cc78 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00000000004dc7c0 RCX: 000000000045c829
RDX: 00000000c0000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000000f2 R14: 00000000004c3773 R15: 00007fc81b35d6d4

Allocated by task 15022:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 kmem_cache_alloc_node+0x148/0x7a0 mm/slab.c:3642
 __alloc_skb+0x9a/0x4c0 net/core/skbuff.c:193
 alloc_skb include/linux/skbuff.h:980 [inline]
 kobject_uevent_env+0x6d1/0xc50 lib/kobject_uevent.c:479
 device_del+0x642/0xa80 drivers/base/core.c:2081
 rollback_registered_many+0x620/0xa70 net/core/dev.c:7230
 rollback_registered+0xd6/0x180 net/core/dev.c:7248
 unregister_netdevice_queue net/core/dev.c:8260 [inline]
 unregister_netdevice_queue+0x1a1/0x220 net/core/dev.c:8253
 unregister_netdevice include/linux/netdevice.h:2442 [inline]
 __tun_detach+0xa8d/0xcf0 drivers/net/tun.c:576
 tun_detach drivers/net/tun.c:586 [inline]
 tun_chr_close+0x41/0x60 drivers/net/tun.c:2671
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 15022:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758
 kfree_skbmem+0x98/0x100 net/core/skbuff.c:586
 __kfree_skb net/core/skbuff.c:646 [inline]
 consume_skb+0xaf/0x330 net/core/skbuff.c:705
 netlink_broadcast_filtered+0x2b3/0x9d0 net/netlink/af_netlink.c:1489
 kobject_uevent_env+0x819/0xc50 lib/kobject_uevent.c:495
 device_del+0x642/0xa80 drivers/base/core.c:2081
 rollback_registered_many+0x620/0xa70 net/core/dev.c:7230
 rollback_registered+0xd6/0x180 net/core/dev.c:7248
 unregister_netdevice_queue net/core/dev.c:8260 [inline]
 unregister_netdevice_queue+0x1a1/0x220 net/core/dev.c:8253
 unregister_netdevice include/linux/netdevice.h:2442 [inline]
 __tun_detach+0xa8d/0xcf0 drivers/net/tun.c:576
 tun_detach drivers/net/tun.c:586 [inline]
 tun_chr_close+0x41/0x60 drivers/net/tun.c:2671
 __fput+0x25f/0x790 fs/file_table.c:210
 task_work_run+0x113/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1d6/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff88809ddd7040
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 62 bytes to the left of
 232-byte region [ffff88809ddd7040, ffff88809ddd7128)
The buggy address belongs to the page:
page:ffffea00027775c0 count:1 mapcount:0 mapping:ffff88809ddd7040 index:0xffff88809ddd7cc0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809ddd7040 ffff88809ddd7cc0 0000000100000006
raw: ffffea0002805160 ffffea000231e9a0 ffff8880a9985a80 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809ddd6f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88809ddd6f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88809ddd7000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                   ^
 ffff88809ddd7080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809ddd7100: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
==================================================================
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=40192 sclass=netlink_route_socket pig=18160 comm=syz-executor.5