Linux Kernel Cadence QSPI Device Tree Parsing Vulnerability

A vulnerability in the Linux kernel's handling of the Cadence QSPI (Quad Serial Peripheral Interface) can lead to improper device tree (DT) parsing for attached flash components. This issue arises from a recent change in how runtime power management (PM) is applied, which can cause duplicate clock disable operations. The problem is exacerbated by incomplete or incorrect DT descriptions for the flashes connected to the QSPI controller. During the probe process, the driver attempts to manage power and clock states, but errors can disrupt this flow, leading to warnings from the clock subsystem about already disabled clocks. The vulnerability requires a specific DT configuration issue to be exploitable.

Impact

The vulnerability can cause runtime power management imbalances, leading to duplicate clock disable warnings and potential disruptions in normal device operation.

Reproduction

The vulnerability can be reproduced by using a device with a Cadence QSPI controller that has a missing or broken device tree description for the attached flashes. The driver will then improperly manage power and clock states, causing warnings about clock disable issues.

Remediation

Users can update to the latest version of the Linux kernel where this vulnerability has been addressed. The specific commit that resolves this issue is available in the Linux stable tree.