# Rust Rt Audit

> Audit a Rust DSP crate for real-time-safety violations — verifies `#![no_std]`, no `alloc` dependency, `panic = "abort"`, runs targeted clippy lints, greps for banned constructs in the hot path, and scans the compiled LLVM-IR for allocator symbols. Designed to be run on any Rust DSP crate before merge. Use when this capability is needed.

- Skill: `tomevault-io/rust-rt-audit` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/rust-rt-audit`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/rust-rt-audit/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/rust-rt-audit

---


# Rust Real-Time Audit

Verify that a Rust DSP crate respects the real-time-safety rules:

1. The crate is `#![no_std]` and does not depend on `alloc`.
2. The crate uses `panic = "abort"` so panics cannot unwind across an FFI or worklet boundary.
3. No clippy-detectable panic-prone constructs (`unwrap`, `expect`, slice indexing, integer overflow) are present.
4. No banned heap/blocking constructs (`Vec::`, `Box::`, `Mutex`, `format!`, `println!`, etc.) appear in the source.
5. The compiled LLVM-IR contains no calls to `__rust_alloc` / `__rust_realloc` / `__rust_dealloc`.

The first four are cheap and run in seconds. The fifth is the authoritative check — a clean grep can lie, but an IR with no allocator symbols cannot.

## Requirements

- **rustup** with a stable toolchain.
- **cargo** (bundled with rustup).
- The crate being audited must compile.

Optional but recommended:
- `clippy` component (`rustup component add clippy`) for the lint pass. The script skips clippy cleanly if it is missing.

## Instructions

The argument is in `$ARGUMENTS`. Pass it directly to the audit script:

```bash
bash "$(dirname "$0")/audit.sh" $ARGUMENTS
```

The argument is the path to the crate directory (the one containing `Cargo.toml`).

## Output sections

| Section | What it reports |
|---|---|
| `NO_STD` | Whether `#![no_std]` is declared in `src/lib.rs` |
| `NO_ALLOC_DEP` | Whether the crate has any dependency on `alloc` (direct or via Cargo.toml) |
| `PANIC_ABORT` | Whether `panic = "abort"` is set in the release profile |
| `CLIPPY` | Lint results from a curated set of panic/allocation-detecting lints |
| `HOT_PATH_GREP` | Grep hits for banned constructs in `src/**.rs` |
| `LLVM_IR_ALLOC` | Whether `__rust_alloc*` symbols appear in the release LLVM-IR |

## Typical usage

```bash
# Audit a single DSP crate
bash audit.sh ./rust/audio-dsp

# Audit every DSP crate in a workspace
for crate in rust/dsp-*; do bash audit.sh "$crate"; done
```

## What to look for

- **`NO_STD` failing** is a structural problem — the crate should be split so DSP code lives in a `no_std` crate and any `std`-dependent code moves to a sibling crate.
- **`NO_ALLOC_DEP` failing** means a transitive dependency pulled in `alloc`. Use `cargo tree -e features` to find the culprit and either gate it behind a feature flag or replace it.
- **`PANIC_ABORT` failing** is a one-line `Cargo.toml` fix.
- **`CLIPPY` or `HOT_PATH_GREP` hits** require code changes — see the agent profile's Real-Time-Safe Rust section for the rationale and the safe replacements.
- **`LLVM_IR_ALLOC` failing despite a clean source grep** usually means a third-party crate is allocating. `cargo tree` + the IR's call site (look at the function name preceding `call __rust_alloc`) identify the source.

---
> Source: [gertsylvest/meta-team](https://github.com/gertsylvest/meta-team) — distributed by [TomeVault](https://tomevault.io).
<!-- tomevault:4.0:skill_md:2026-06-16 -->