DF-4015

mps_user_command leaks one mps_command per timed-out MPSIO_MPS_COMMAND (shared pool exhaustion starves the storage stack)

Summary

The wait error path does 'goto Ret' which skips the RetFreeUnlocked block - the mps_command is never returned to sc->req_list. Each timed-out MPSIO_MPS_COMMAND permanently removes one slot from the finite pool shared with the SCSI I/O path -> ENOMEM for all management ioctls and eventual I/O starvation of the boot disk. Folded into the DF-4014 abandon-policy fix.

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Severity: Low
Status: new
Bucket: Base system — drivers
Confidence: certain
Pass: 2 · GLM 5.3 second pass
CVSS 3.1: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-401
File: sys/dev/raid/mps/mps_user.c
Lines: 705-737
Area: dev
Discovered: 2026-09-17
Updated: 2026-09-17

Team triage

untriaged

priority: — · owner: —

PoC verification

untested

Status: untested
Reproduced: no
Impact: mps_user_command leaks one mps_command per timed-out MPSIO_MPS_COMMAND (goto Ret skips RetFreeUnlocked) - operator drains the finite command pool shared with SCSI I/O -> ENOMEM for management ioctls and eventual I/O starvation of the boot disk.
Confidence: certain
Tested: 2026-09-17 14:39:57
Attempts: 0
Runtime: —
Code hash: —
Guest: —
Build cmd: —
Run cmd: —

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Fix verification

not_testable

Fix status: not_testable
Baseline reproduced: no
Patched reproduced: no
Confidence: certain
Tested: 2026-09-17 14:39:57
Runtime: —
Kernel: per-fix-DF-4015
fix.diff: findings/poc/DF-4015/fix.diff
Runner: df-bsd-reviewer

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PoC verification

Evidence pack

findings/poc/DF-4015 · 2 files

File	Type	Description	Size
README.md	file		242 B	↓ raw
verdict.json	file		957 B	view raw

README.md file

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DF-4015

Low/Info finding — PoC skipped per contract (hardware-gated / dead code). Source citations in the pass-2 result block.

Fix: free/reclaim the command once provably no longer in flight (folded into the DF-4014 abandon-policy fix)

Fix verification

not_testable

baseline no→ patch + rebuild →patched clean

free/reclaim the command once provably no longer in flight (folded into the DF-4014 abandon-policy fix)

source-only

per-fix-DF-4015

Confirmed kernel references

Detail

Exploit chain

[]

Evidence (decisive lines)

source-only; path:line citations in pass-2 result block

Verdict

source-verified; HW-gated (needs mps adapter + slow FW)