Linux Kernel x86 Resctrl NULL Pointer Dereference Vulnerability

A vulnerability in the Linux kernel's x86/resctrl component can lead to a NULL pointer dereference when creating a new control group on platforms without cache occupancy monitors. The issue arises because the logic added in a previous commit to allocate the cleanest CLOSID by searching for the fewest dirty cache lines depends on values from the llc_occupancy counters. On platforms lacking these counters, the array needed for this operation is not properly allocated, causing the NULL pointer dereference.

Impact

Exploitation of this vulnerability leads to a NULL pointer dereference, causing a crash or undefined behavior in the system.

Remediation

The vulnerability has been addressed in the Linux kernel. Users should upgrade to the latest version where this issue has been fixed.