# DF-3186 -- verification pack

Finding: hammer_upgrade_undo_4 loop cannot terminate on incongruent alloc_offset

Status: **not_reproduced** / impact **denial_of_service** / confidence certain

## What was run
guest: cc -O -o patch_undo patch_undo.c; image: newfs_hammer, first mount clean, umount, patch version=3 + alloc skew, remount

## How to reproduce
```
guest: mount_hammer /dev/vn0 /mnt/h1 (expect EIO: Failed to recover)
```

## Expected
mount rejects the incongruent alloc_offset with EIO; SET_VERSION unreachable

See VERDICT.md for the full narrative and verdict.json for the persisted
machine verdict. Artifacts: patch_undo.c, run.log.