==================================================================
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x2ef/0x340 fs/ext4/dir.c:86
Read of size 1 at addr ffff888089e4c000 by task syz-executor.0/8387
FAT-fs (loop5): error, fat_get_cluster: invalid cluster chain (i_pos 970769)

CPU: 1 PID: 8387 Comm: syz-executor.0 Not tainted 4.14.183-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
FAT-fs (loop5): Filesystem has been set read-only
 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+0x2ef/0x340 fs/ext4/dir.c:86
 ext4_readdir+0x819/0x27e0 fs/ext4/dir.c:240
FAT-fs (loop5): error, fat_free: invalid cluster chain (i_pos 970769)
 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: 0033:0x45ca69
RSP: 002b:00007f8dd880bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00000000004dcac0 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000000f1 R14: 00000000004c39aa R15: 00007f8dd880c6d4

Allocated by task 8273:
 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
 kmem_cache_alloc+0x124/0x3c0 mm/slab.c:3552
 getname_flags+0xc8/0x550 fs/namei.c:138
 do_sys_open+0x202/0x3e0 fs/open.c:1075
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 8273:
 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]
 kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758
 putname+0xcd/0x110 fs/namei.c:259
 do_sys_open+0x233/0x3e0 fs/open.c:1090
 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 ffff888089e4cd80
 which belongs to the cache names_cache of size 4096
The buggy address is located 3456 bytes to the left of
 4096-byte region [ffff888089e4cd80, ffff888089e4dd80)
The buggy address belongs to the page:
page:ffffea0002279300 count:1 mapcount:0 mapping:ffff888089e4cd80 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff888089e4cd80 0000000000000000 0000000100000001
raw: ffffea0001698720 ffffea00029e7f20 ffff8880aa9dacc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888089e4bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888089e4bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888089e4c000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff888089e4c080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888089e4c100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
FAT-fs (loop5): error, fat_get_cluster: invalid cluster chain (i_pos 970769)
FAT-fs (loop5): error, fat_free: invalid cluster chain (i_pos 970769)