# CVE-2025-68356: gfs2: Prevent recursive memory reclaim

> A flaw in the Linux kernel GFS2 filesystem allows local attackers to cause a deadlock or stack overflow via recursive memory reclaim, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2025
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-73105, BELL-CVE-2025-68356, DEBIAN-CVE-2025-68356, GHSA-cvcc-7fqf-pp94, ROOT-OS-UBUNTU-2404-CVE-2025-68356, UBUNTU-CVE-2025-68356

## What is CVE-2025-68356?

CVE-2025-68356 is a denial of service vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

gfs2: Prevent recursive memory reclaim

Function new_inode() returns a new inode with inode->i_mapping->gfp_mask
set to GFP_HIGHUSER_MOVABLE.  This value includes the __GFP_FS flag, so
allocations in that address space can recurse into filesystem memory
reclaim.  We don't want that to happen because it can consume a
significant amount of stack memory.

Worse than that is that it can also deadlock: for example, in several
places, gfs2_unstuff_dinode() is called inside filesystem transactions.
This calls filemap_grab_folio(), which can allocate a new folio, which
can trigger memory reclaim.  If memory reclaim recurses into the
filesystem and starts another transaction, a deadlock will ensue.

To fix these kinds of problems, prevent memory reclaim from recursing
into filesystem code by making sure that the gfp_mask of inode address
spaces doesn't include __GFP_FS.

The "meta" and resource group address spaces were already using GFP_NOFS
as their gfp_mask (which doesn't include __GFP_FS).  The default value
of GFP_HIGHUSER_MOVABLE is less restrictive than GFP_NOFS, though.  To
avoid being overly limiting, use the default value and only knock off
the __GFP_FS flag.  I'm not sure if this will actually make a
difference, but it also shouldn't hurt.

This patch is loosely based on commit ad22c7a043c2 ("xfs: prevent stack
overflows from page cache allocation").

Fixes xfstest generic/273.

## Which versions are affected by CVE-2025-68356?


## How do I fix CVE-2025-68356?

Apply the vendor's patch.

## Is CVE-2025-68356 being exploited?

There is no known exploitation of CVE-2025-68356 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68356 and fix it if it is affected.

What it is: CVE-2025-68356 is a denial of service vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68356 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

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/CVE-2025-68356/ (Markdown: https://insights.sbomify.com/CVE-2025-68356/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68356
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68356
- OSV: https://osv.dev/vulnerability/CVE-2025-68356

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68356/
Summaries are generated and may contain mistakes; the official description above is the record.