fsck.vfat -n exited with status code 1
fsck.fat 4.2 (2021-01-31)
Wrong checksum for long file name "file0".
  (Short name F\377\377\377 may have changed without updating the long name)
  Not auto-correcting this.
Wrong checksum for long file name "file.cold".
  (Short name FILE~1.C\377\225 may have changed without updating the long name)
  Not auto-correcting this.
/file0
  Bad short file name (F\377\377\377).
  Auto-renaming it.
  Renamed to FSCK0000.000
/FSCK0000.000
 Start does point to root directory. Deleting dir. 
/í
  Bad start cluster 1. Truncating file.
/í
  File size is 10 bytes, cluster chain length is 0 bytes.
  Truncating file to 0 bytes.
/file.cold
  Directory has non-zero size. Fixing it.
/file.cold/syzkalle.rsy
  Expected a valid '.' entry in this slot.
  Moving entry down.
/file.cold/llersyzk.all
  Expected a valid '..' entry in this slot.
  Moving entry down.
/file.cold/
  Bad short file name ().
  Auto-renaming it.
  Renamed to FSCK0000.000
/file.cold/llersyzk.all
  Bad short file name (llersyzk.all).
  Auto-renaming it.
  Renamed to FSCK0000.001
/file.cold/yzkaller.syz
  Start cluster beyond limit (31091 > 8). Truncating file.
/file.cold/yzkaller.syz
  File size is 1818323834 bytes, cluster chain length is 0 bytes.
  Truncating file to 0 bytes.
/file.cold/syzkalle.rsy
  Directory has non-zero size. Fixing it.
/file.cold/syzkalle.rsy
  Start cluster beyond limit (29554 > 8). Truncating file.
/file.cold/FSCK0000.001
  File size is 1936876800 bytes, cluster chain length is 0 bytes.
  Truncating file to 0 bytes.
Volume label 'SYZKALLER' stored in root directory and label '' stored in boot sector and different.
  Auto-copying volume label from root directory to boot sector.
Reclaimed 3 unused clusters (49152 bytes).

Leaving filesystem unchanged.
/tmp/1536662377.img: 9 files, 2/7 clusters