CVE-2026-46093 mm/vmalloc: take vmap_purge_lock in shrinker

In the Linux kernel, the following vulnerability has been resolved: mm/vmalloc: take vmappurgelock in shrinker decayvapoolnode can be invoked concurrently from two paths: purgevmaparealazy when pools are being purged, and the shrinker via vmapnodeshrinkscan. However, decayvapoolnode is not safe t...