CVE-2025-40346

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

arch_topology: Fix incorrect error check in topology_parse_cpu_capacity()

Fix incorrect use of PTR_ERR_OR_ZERO() in topology_parse_cpu_capacity()

which causes the code to proceed with NULL clock pointers. The current

logic uses !PTR_ERR_OR_ZERO(cpu_clk) which evaluates to true for both

valid pointers and NULL, leading to potential NULL pointer dereference

in clk_get_rate().

Per include/linux/err.h documentation, PTR_ERR_OR_ZERO(ptr) returns:

"The error code within @ptr if it is an error pointer; 0 otherwise."

This means PTR_ERR_OR_ZERO() returns 0 for both valid pointers AND NULL

pointers. Therefore !PTR_ERR_OR_ZERO(cpu_clk) evaluates to true (proceed)

when cpu_clk is either valid or NULL, causing clk_get_rate(NULL) to be

called when of_clk_get() returns NULL.

Replace with !IS_ERR_OR_NULL(cpu_clk) which only proceeds for valid

pointers, preventing potential NULL pointer dereference in clk_get_rate().

/// 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