# GSD-2021-1002124: mm: filemap: check if THP has hwpoisoned subpage for PMD page fault

> A missing check for hardware-poisoned subpages in Transparent Huge Pages during PMD faults can lead to system instability or crashes.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Nov 2021

## What is GSD-2021-1002124?

GSD-2021-1002124 is a memory corruption vulnerability in Kernel, published on 14 Nov 2021. 

### Official description

mm: filemap: check if THP has hwpoisoned subpage for PMD page fault

This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven.
This ID is fixed in Linux Kernel version v5.14.16 by commit 6ac017254b597709f39a083e1b1dfe09ef684f04, it was introduced in version v4.8 by commit 800d8c63b2e989c2e349632d1648119bf5862f01. For more details please see the references link.

## Which versions are affected by GSD-2021-1002124?

1 open source package ship an affected version, including Kernel.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Kernel` | Linux | All versions | None |

## How do I fix GSD-2021-1002124?

No fix has been published for GSD-2021-1002124 yet. Limit exposure of the affected software until one is available.

## Is GSD-2021-1002124 being exploited?

There is no known exploitation of GSD-2021-1002124 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GSD-2021-1002124 and fix it if it is affected.

What it is: GSD-2021-1002124 is a memory corruption vulnerability in Kernel, published on 14 Nov 2021. 
Exploitation: There is no known exploitation of GSD-2021-1002124 in the wild and no public exploit code.

Affected packages and fixed versions:
- Kernel (Linux): affected all versions; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GSD-2021-1002124/ (Markdown: https://insights.sbomify.com/GSD-2021-1002124/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GSD-2021-1002124

---
From sbomify Insights: https://insights.sbomify.com/GSD-2021-1002124/
Summaries are generated and may contain mistakes; the official description above is the record.