Linux Kernel Cacheinfo Shared CPU Map Handling Vulnerability

A vulnerability in the Linux kernel's cacheinfo management has been addressed. The issue arose in the shared_cpu_map configuration, which incorrectly assumed that caches with the same index were shared between CPUs. This assumption led to slab-out-of-bounds access when CPUs had differing cache hierarchies. Additionally, mismatches in the shared_cpu_map occurred when caches were not indexed identically across CPUs. The vulnerability was resolved by modifying the shared_cpu_map setup process to accurately reflect cache sharing across all CPUs, regardless of index discrepancies.

Impact

The vulnerability could cause out-of-bounds memory access, potentially leading to memory corruption or other unintended behavior.