# CVE-2025-37837: iommu/tegra241-cmdqv: Fix warnings due to dmam_free_coherent()

> A bug in the Tegra241 CMDQV IOMMU driver causes kernel warnings and potential instability during error handling, leading to denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 May 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-37837, DEBIAN-CVE-2025-37837, GHSA-q7q8-5x36-4r88, ROOT-OS-UBUNTU-2204-CVE-2025-37837, UBUNTU-CVE-2025-37837

## What is CVE-2025-37837?

CVE-2025-37837 is a medium-severity vulnerability in Linux kernel, published on 9 May 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:

iommu/tegra241-cmdqv: Fix warnings due to dmam_free_coherent()

Two WARNINGs are observed when SMMU driver rolls back upon failure:
 arm-smmu-v3.9.auto: Failed to register iommu
 arm-smmu-v3.9.auto: probe with driver arm-smmu-v3 failed with error -22
 ------------[ cut here ]------------
 WARNING: CPU: 5 PID: 1 at kernel/dma/mapping.c:74 dmam_free_coherent+0xc0/0xd8
 Call trace:
  dmam_free_coherent+0xc0/0xd8 (P)
  tegra241_vintf_free_lvcmdq+0x74/0x188
  tegra241_cmdqv_remove_vintf+0x60/0x148
  tegra241_cmdqv_remove+0x48/0xc8
  arm_smmu_impl_remove+0x28/0x60
  devm_action_release+0x1c/0x40
 ------------[ cut here ]------------
 128 pages are still in use!
 WARNING: CPU: 16 PID: 1 at mm/page_alloc.c:6902 free_contig_range+0x18c/0x1c8
 Call trace:
  free_contig_range+0x18c/0x1c8 (P)
  cma_release+0x154/0x2f0
  dma_free_contiguous+0x38/0xa0
  dma_direct_free+0x10c/0x248
  dma_free_attrs+0x100/0x290
  dmam_free_coherent+0x78/0xd8
  tegra241_vintf_free_lvcmdq+0x74/0x160
  tegra241_cmdqv_remove+0x98/0x198
  arm_smmu_impl_remove+0x28/0x60
  devm_action_release+0x1c/0x40

This is because the LVCMDQ queue memory are managed by devres, while that
dmam_free_coherent() is called in the context of devm_action_release().

Jason pointed out that "arm_smmu_impl_probe() has mis-ordered the devres
callbacks if ops->device_remove() is going to be manually freeing things
that probe allocated":
https://lore.kernel.org/linux-iommu/20250407174408.GB1722458@nvidia.com/

In fact, tegra241_cmdqv_init_structures() only allocates memory resources
which means any failure that it generates would be similar to -ENOMEM, so
there is no point in having that "falling back to standard SMMU" routine,
as the standard SMMU would likely fail to allocate memory too.

Remove the unwind part in tegra241_cmdqv_init_structures(), and return a
proper error code to ask SMMU driver to call tegra241_cmdqv_remove() via
impl_ops->device_remove(). Then, drop tegra241_vintf_free_lvcmdq() since
devres will take care of that.

## Which versions are affected by CVE-2025-37837?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-37837?

Apply the vendor's patch.

## Is CVE-2025-37837 being exploited?

There is no known exploitation of CVE-2025-37837 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-37837 and fix it if it is affected.

What it is: CVE-2025-37837 is a medium-severity vulnerability in Linux kernel, published on 9 May 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-2025-37837 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-37837/ (Markdown: https://insights.sbomify.com/CVE-2025-37837/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37837
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37837
- OSV: https://osv.dev/vulnerability/CVE-2025-37837

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37837/
Summaries are generated and may contain mistakes; the official description above is the record.