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.
Orphaned long file name part "file.cold"
  Auto-deleting.
/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.
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 4 unused clusters (65536 bytes).

Leaving filesystem unchanged.
/tmp/17990199.img: 4 files, 1/7 clusters