CVE-2022-49434

/// Technical 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) (

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References