Linux Kernel PowerPC Performance Monitoring Unit PMI Handling Vulnerability

A vulnerability in the Linux kernel's PowerPC architecture has been addressed, related to the handling of Performance Monitoring Unit (PMU) interrupts. The issue arose because a new function, 'pmi_irq_pending', was introduced to check for pending PMIs in the Processor Affinity Control Area (PACA). This function was used in 'power_pmu_disable' to issue a warning if a PMI was pending but no overflowed Performance Monitoring Counter (PMC) was active. However, this warning was unnecessary, as PMCs can overflow in inactive events. The vulnerability could lead to improper handling of PMIs, where pending interrupts from inactive events are ignored, potentially causing missed performance monitoring events.

Impact

The vulnerability could result in improper handling of PMU interrupts, leading to missed performance monitoring events on PowerPC systems.

Remediation

Users can apply the latest patches available in the Linux kernel repository to address this vulnerability.