# CVE-2022-48868: dmaengine: idxd: Let probe fail when workqueue cannot be enabled

> A flaw in the Linux kernel idxd driver allows a null pointer dereference and system crash during driver removal if workqueue initialization fails.

- **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:** 21 Aug 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-48868, GHSA-35cf-498m-vj28, UBUNTU-CVE-2022-48868

## What is CVE-2022-48868?

CVE-2022-48868 is a medium-severity vulnerability in Linux kernel, published on 21 Aug 2024. 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:

dmaengine: idxd: Let probe fail when workqueue cannot be enabled

The workqueue is enabled when the appropriate driver is loaded and
disabled when the driver is removed. When the driver is removed it
assumes that the workqueue was enabled successfully and proceeds to
free allocations made during workqueue enabling.

Failure during workqueue enabling does not prevent the driver from
being loaded. This is because the error path within drv_enable_wq()
returns success unless a second failure is encountered
during the error path. By returning success it is possible to load
the driver even if the workqueue cannot be enabled and
allocations that do not exist are attempted to be freed during
driver remove.

Some examples of problematic flows:
(a)

 idxd_dmaengine_drv_probe() -> drv_enable_wq() -> idxd_wq_request_irq():
 In above flow, if idxd_wq_request_irq() fails then
 idxd_wq_unmap_portal() is called on error exit path, but
 drv_enable_wq() returns 0 because idxd_wq_disable() succeeds. The
 driver is thus loaded successfully.

 idxd_dmaengine_drv_remove()->drv_disable_wq()->idxd_wq_unmap_portal()
 Above flow on driver unload triggers the WARN in devm_iounmap() because
 the device resource has already been removed during error path of
 drv_enable_wq().

(b)

 idxd_dmaengine_drv_probe() -> drv_enable_wq() -> idxd_wq_request_irq():
 In above flow, if idxd_wq_request_irq() fails then
 idxd_wq_init_percpu_ref() is never called to initialize the percpu
 counter, yet the driver loads successfully because drv_enable_wq()
 returns 0.

 idxd_dmaengine_drv_remove()->__idxd_wq_quiesce()->percpu_ref_kill():
 Above flow on driver unload triggers a BUG when attempting to drop the
 initial ref of the uninitialized percpu ref:
 BUG: kernel NULL pointer dereference, address: 0000000000000010

Fix the drv_enable_wq() error path by returning the original error that
indicates failure of workqueue enabling. This ensures that the probe
fails when an error is encountered and the driver remove paths are only
attempted when the workqueue was enabled successfully.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-48868?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48868?

Apply the vendor's patch.

## Is CVE-2022-48868 being exploited?

There is no known exploitation of CVE-2022-48868 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-2022-48868 and fix it if it is affected.

What it is: CVE-2022-48868 is a medium-severity vulnerability in Linux kernel, published on 21 Aug 2024. 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-2022-48868 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-2022-48868/ (Markdown: https://insights.sbomify.com/CVE-2022-48868/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48868
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48868
- OSV: https://osv.dev/vulnerability/CVE-2022-48868

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48868/
Summaries are generated and may contain mistakes; the official description above is the record.