# DF-0118 — REPRODUCED (source-only, requires kdmsg peer)

## Verdict
REPRODUCED (source-only, requires kdmsg peer)

## Mechanism
diskiodone eof path (:637-639) and disk_blk_open paths never kfree(iost/openst) on kdmsg teardown. kdmsg_state_free (kern_dmsg.c:1754-1764) has no destructor for state->any.any. Peer can repeat OPEN/READ-WITH-DELETE+abort cycles to exhaust M_DEVBUF.

## Source trace
- File: `sys/kern/subr_diskiocom.c`
- References: sys/kern/subr_diskiocom.c:637, sys/kern/kern_dmsg.c:1754

## 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
Free state->any.any in kdmsg_state_free if non-NULL. Matches finding proposal.