# DF-3256 - verification verdict

**status**: not_reproduced | **impact**: none | **confidence**: certain | attempts: 0

## Narrative

Race-mechanics-certain from source; live hit deliberately not attempted (statistical window between vfc_refcount++ at vfs_syscalls.c:359 and the read at procfs_vfsops.c:73, impact cosmetic - stale /proc entries only, all procfs ops re-resolve by pid). Two concurrent mounts can both observe refcount==2 and both skip at_exit(procfs_exit); the symmetric unmount gate is :109-110. Prior pack (untested) analysis re-confirmed this pass; fix registers the handler once (flag-guarded, never deregistered - procfs_exit is a no-op with no pfsnodes); compiled in the F40FIX build.

## Fix validation

- fix_status: compile_validated
- fix.diff applied in the F40FIX verification kernel build (RC=0, zero -Werror errors); no runtime A/B for this item (line-certain hardening)

## Kernel references

- sys/vfs/procfs/procfs_vfsops.c:73
- sys/vfs/procfs/procfs_vfsops.c:109
- sys/kern/vfs_syscalls.c:359

## Reproduce

See the artifacts in this directory; run.log = stock-kernel baseline, run.fixed.log = F40FIX fixed-kernel A/B where one exists.