==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x2f9/0x340 fs/ext4/dir.c:68
Read of size 2 at addr ffff88804cd89002 by task syz-executor.0/11361

CPU: 1 PID: 11361 Comm: syz-executor.0 Not tainted 4.14.184-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+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc 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+0xa9/0x2b9 mm/kasan/report.c:393
 __ext4_check_dir_entry+0x2f9/0x340 fs/ext4/dir.c:68
 ext4_readdir+0x819/0x27e0 fs/ext4/dir.c:240
 iterate_dir+0x1a0/0x5e0 fs/readdir.c:52
 SYSC_getdents fs/readdir.c:269 [inline]
 SyS_getdents+0x132/0x260 fs/readdir.c:250
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca59
RSP: 002b:00007f9ef14d3c78 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00000000004dcf60 RCX: 000000000045ca59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000000f6 R14: 00000000004c3a00 R15: 00007f9ef14d46d4

Allocated by task 11347:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc_array include/linux/slab.h:607 [inline]
 kcalloc include/linux/slab.h:618 [inline]
 iter_file_splice_write+0x143/0xa10 fs/splice.c:692
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1018
 splice_direct_to_actor+0x27e/0x730 fs/splice.c:973
 do_splice_direct+0x164/0x210 fs/splice.c:1061
 do_sendfile+0x469/0xaf0 fs/read_write.c:1441
 SYSC_sendfile64 fs/read_write.c:1496 [inline]
 SyS_sendfile64+0x9b/0x110 fs/read_write.c:1488
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 11347:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 iter_file_splice_write+0x464/0xa10 fs/splice.c:776
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1018
 splice_direct_to_actor+0x27e/0x730 fs/splice.c:973
 do_splice_direct+0x164/0x210 fs/splice.c:1061
 do_sendfile+0x469/0xaf0 fs/read_write.c:1441
 SYSC_sendfile64 fs/read_write.c:1496 [inline]
 SyS_sendfile64+0x9b/0x110 fs/read_write.c:1488
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff88804cd89000
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 2 bytes inside of
 256-byte region [ffff88804cd89000, ffff88804cd89100)
The buggy address belongs to the page:
page:ffffea0001336240 count:1 mapcount:0 mapping:ffff88804cd89000 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88804cd89000 0000000000000000 000000010000000c
raw: ffffea000233d6a0 ffffea00025f60a0 ffff8880aa8007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804cd88f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804cd88f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804cd89000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88804cd89080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88804cd89100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================
audit: type=1326 audit(1592283017.793:21): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=11375 comm="syz-executor.3" exe="/root/syz-executor.3" sig=31 arch=c000003e syscall=228 compat=0 ip=0x45f89a code=0xffff0000