CVE-2025-71301

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 vmap_locked, which led to errors such
as show below.

[  122.292030] WARNING: CPU: 3 PID: 1413 at drivers/gpu/drm/drm_gem_shmem_helper.c:390 drm_gem_shmem_vmap_locked+0x3a3/0x6f0

[  122.468066] WARNING: CPU: 3 PID: 1413 at drivers/gpu/drm/drm_gem_shmem_helper.c:293 drm_gem_shmem_pin_locked+0x1fe/0x350

[  122.563504] WARNING: CPU: 3 PID: 1413 at drivers/gpu/drm/drm_gem_shmem_helper.c:234 drm_gem_shmem_get_pages_locked+0x23c/0x370

[  122.662248] WARNING: CPU: 2 PID: 1413 at drivers/gpu/drm/drm_gem_shmem_helper.c:452 drm_gem_shmem_vunmap_locked+0x101/0x330

Only export the new vmap/vunmap helpers for Kunit tests. These are
not interfaces for regular drivers.