CVE-2025-71301 drm/tests: shmem: Hold reservation lock around vmap/vunmap

In the Linux kernel, the following vulnerability has been resolved: drm/tests: shmem: Hold reservation lock around vmap/vunmap Acquire and release the GEM object's reservation lock around vmap and vunmap operations. The tests use vmaplocked, which led to errors such as show below. 122.292030...