Linux Kernel Regmap Memory Leak Vulnerability in Maple Cache Handling

A memory leak vulnerability has been identified in the Linux kernel's regmap subsystem, specifically within the maple regcache implementation. The issue arises in the 'regcache_maple_write' function, where a new block, referred to as 'entry', is allocated to merge adjacent ranges. This 'entry' is then intended to be stored using the 'mas_store_gfp()' function. However, if 'mas_store_gfp()' fails, the allocated 'entry' is not freed, leading to a memory leak. The vulnerability affects the Linux kernel stable tree.

Impact

The vulnerability causes a memory leak, where allocated memory is not properly freed, potentially leading to increased memory usage and exhaustion over time.

Reproduction

The vulnerability can be reproduced by triggering a failure in the 'mas_store_gfp()' function while writing to the regcache maple. This failure will result in the 'entry' block remaining allocated and not being freed, causing a memory leak.

Remediation

The vulnerability has been addressed in the Linux kernel. Users can upgrade to the latest version to apply the fix.