Linux Kernel Unchecked MSR Access Vulnerability in Intel LBR Handling

A vulnerability in the Linux kernel's handling of Intel Last Branch Record (LBR) data has been addressed. The issue arose from an unchecked Model Specific Register (MSR) access error when writing to a specific LBR-related MSR. This error was triggered by a fuzzer, indicating a potential flaw in how the kernel manages LBR data from Intel processors, particularly on systems with certain LBR formats and TSX (Transactional Synchronization Extensions) settings.

Impact

Exploitation of this vulnerability could lead to unchecked MSR access errors, potentially allowing for improper handling of LBR data, which could be exploited in certain performance monitoring scenarios.