=== DF-0794 PATCHED-KERNEL re-run (Phase 8 "after") ===
uname: DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #1: Mon Jul 13 19:38:48 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64
kernel hash: 9bda5319a0f577f760b48ae11528c73e502fe8b488123959f9902606604183b7

--- creating 4 MB image ---
[newfs] /dev/vn0: media size   4.00MB
[newfs] Warning: Block size restricts cylinders per group to 107.
[newfs] /dev/vn0:	8192 sectors in 2 cylinders of 1 tracks, 4096 sectors
[newfs] 	4.0MB in 1 cyl groups (107 c/g, 214.00MB/g, 512 i/g)
[newfs] super-block backups (for fsck -b #) at:
[newfs]  32

--- patching superblock (fs_ncg=0) ---
BEFORE: magic=0x00011954 ncg=1 bsize=16384 sbsize=2048 cssize=2048 cstotal.cs_nifree=509 clean=1 postblformat=1 contigsumsize=7
AFTER : magic=0x00011954 ncg=0 bsize=16384 sbsize=2048 cssize=2048 cstotal.cs_nifree=1 clean=1 postblformat=1 contigsumsize=7
patched /tmp/df0794.img: fs_ncg=0, fs_cstotal.cs_nifree=1, fs_clean=1

--- attaching + mounting RW ---
mount: warning: fstype in disklabel not set to anything I understand
attempting to mount with -t ufs
mount_ufs: /dev/vn0 on /tmp/df0794_mnt: incorrect super block
RUN_RC=1

=== INTERPRETATION ===
The patched kernel's new validation block in ffs_mountfs
(ffs_vfsops.c:647+) rejects the crafted superblock with EINVAL
before any divisor in ffs_dirpref/ffs_valloc is reached. dmesg
shows the diagnostic kprintf:
    ffs_mountfs: corrupt superblock: ncg=0 ipg=512 frag=8
No #DE trap. No panic. Guest stayed up. Fix CONFIRMED.

=== REGRESSION CHECK (valid image still mounts) ===
MOUNT_VALID=OK
MKDIR_VALID=OK
drwxr-xr-x  2 root  wheel  512 Jul 13 19:46 /tmp/okmnt/regression_test_dir