Linux Kernel DRM VMA Manager Vulnerability Allowing One-Time Offset Node Approval

A vulnerability in the Linux kernel's Direct Rendering Manager (DRM) VMA (Virtual Memory Area) manager has been addressed. The issue allowed DRM drivers to safely check and permit 'drm_vma_offset_node' for a DRM file only once. Previously, drivers had to manage each 'drm_vma_node_allow()' call and subsequently revoke it to avoid memory leaks. The vulnerability has been resolved by introducing 'drm_vma_node_allow_once()', enabling drivers to make non-refcounted allowance without the need for tracking.

Impact

The vulnerability could lead to memory leaks by requiring drivers to manually revoke VMA allowances, potentially causing inefficient memory management or exhaustion.