CVE-2022-48881

What it actually does

Missing pci_dev_put() call after pci_get_domain_bus_and_slot() in amd_pmc_probe error path causes reference count leak on the PCI device.

Why it matters to the business

Gradual resource exhaustion on AMD-based Linux systems can lead to driver instability, increased memory pressure, and potential need for reboots in production environments.

How an attack unfolds

An attacker with local access or ability to trigger repeated device probe failures (e.g., via hardware manipulation or error injection during initialization) can cause the reference count to leak each time the error path executes.

How to fix it

Upgrade the Linux kernel to a version containing commit 3944162821295993ec89992dec98ab6be6306cc0; Android devices require SoC firmware dated 2020-12-05 or newer.

How to confirm the fix worked

Confirm the fix commit is present in the running kernel source tree or verify updated kernel package versions contain the corrected amd_pmc.c file.

Typical attack path

1. Cause amd_pmc_probe to enter an error path after pci_get_domain_bus_and_slot succeeds
2. Repeat probe failure conditions to accumulate leaked references
3. Observe eventual memory pressure or module unload failures

How to detect it

Inspect kernel logs for amd_pmc_probe error paths without corresponding put operations; correlate with rising PCI reference counts or module memory usage over time.

What your security team should do

• Apply the referenced kernel commit or newer stable release to all affected systems
• Prioritize updates on AMD platforms running the PMC driver
• Review boot and probe logs for repeated amd_pmc errors as an interim indicator