Linux Kernel Alloc Tag Lock Acquisition Vulnerability in Top Users Function

A vulnerability exists in the Linux kernel's memory allocation tagging feature. The issue arises in the 'alloc_tag_top_users()' function, which improperly attempts to lock a module's modification lock when the allocation tagging control type is not properly initialized or allocated. This misstep can lead to a general protection fault, causing a crash. The problem is exacerbated when memory profiling is disabled at boot, allowing the issue to be easily triggered.

Impact

The vulnerability causes a null pointer dereference, leading to a general protection fault and a crash, particularly when memory allocation fails.

Reproduction

The vulnerability can be reproduced by compiling the Linux kernel with memory profiling support, but disabling it at boot. This creates a scenario where the allocation tagging control type is not initialized, yet the 'alloc_tag_top_users()' function still attempts to acquire a lock, resulting in a crash.

Remediation

Users can update to the latest version of the Linux kernel where this vulnerability has been fixed.