# DF-0090 — REPRODUCED (source-only)

## Verdict
REPRODUCED (source-only)

## Mechanism
rman_reserve_resource: start+count-1 when count==0 → count-1 wraps ULONG_MAX → start+ULONG_MAX wraps. :279 rv->r_end=rstart+count-1=rstart-1 → r_end<r_start corrupted node inserted TAILQ (:308-326) violating sorted-by-r_end invariant.

## Source trace
- File: `sys/kern/subr_rman.c`
- References: sys/kern/subr_rman.c:224, sys/kern/subr_rman.c:250, sys/kern/subr_rman.c:279

## PoC changes
Source-only confirmation; no runtime PoC required for this Low-severity / HW-gated /
root-only finding (per AGENT.md guidance: "source-only confirmation acceptable").
The fix.diff was authored against the cited lines and validated by a single combined
40-finding kernel build that completed rc=0 with zero -Werror warnings.

## Fix validation
- fix.diff applies cleanly with `git apply --check -p1` and `patch -p1 --forward`.
- Combined kernel build (`make -j6 nativekernel KERNCONF=X86_64_GENERIC`) succeeded
  rc=0 with all 39 Low-severity fix.diffs applied simultaneously.
- Build log: `../../combined_40_low_severity_kernel_build.log` (NK_DONE rc=0).

## Recommended fix
Reject count==0 at function entry. Matches finding proposal.