# CVE-2022-49434: PCI: Avoid pci_dev_lock() AB/BA deadlock with sriov_numvfs_store()

> A deadlock in the Linux kernel PCI subsystem can cause a denial of service when specific SR-IOV and reset operations occur concurrently.

- **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:** 26 Feb 2025
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-49434, GHSA-fxw3-5jmj-82p9, UBUNTU-CVE-2022-49434

## What is CVE-2022-49434?

CVE-2022-49434 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 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:

PCI: Avoid pci_dev_lock() AB/BA deadlock with sriov_numvfs_store()

The sysfs sriov_numvfs_store() path acquires the device lock before the
config space access lock:

  sriov_numvfs_store
    device_lock                 # A (1) acquire device lock
    sriov_configure
      vfio_pci_sriov_configure  # (for example)
        vfio_pci_core_sriov_configure
          pci_disable_sriov
            sriov_disable
              pci_cfg_access_lock
                pci_wait_cfg    # B (4) wait for dev->block_cfg_access == 0

Previously, pci_dev_lock() acquired the config space access lock before the
device lock:

  pci_dev_lock
    pci_cfg_access_lock
      dev->block_cfg_access = 1 # B (2) set dev->block_cfg_access = 1
    device_lock                 # A (3) wait for device lock

Any path that uses pci_dev_lock(), e.g., pci_reset_function(), may
deadlock with sriov_numvfs_store() if the operations occur in the sequence
(1) (2) (3) (4).

Avoid the deadlock by reversing the order in pci_dev_lock() so it acquires
the device lock before the config space access lock, the same as the
sriov_numvfs_store() path.

[bhelgaas: combined and adapted commit log from Jay Zhou's independent
subsequent posting:
https://lore.kernel.org/r/20220404062539.1710-1-jianjay.zhou@huawei.com]

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2022-49434?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49434?

Apply the vendor's patch.

## Is CVE-2022-49434 being exploited?

There is no known exploitation of CVE-2022-49434 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-2022-49434 and fix it if it is affected.

What it is: CVE-2022-49434 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 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-2022-49434 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-2022-49434/ (Markdown: https://insights.sbomify.com/CVE-2022-49434/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49434
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49434
- OSV: https://osv.dev/vulnerability/CVE-2022-49434

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49434/
Summaries are generated and may contain mistakes; the official description above is the record.