These two patches fix a problem with the madvise purging code for the shmem helpers where the mmaping for a purged buffer wouldn't get invalidated correctly. This presumably ends up as a security hole where the mapping can be accessed from user-space to read and write random pages from other buffers. This is currently affecting Panfrost. The second patch is a v2 from a patch that was sent standalone.
There is a WIP IGT test for Panfrost which demonstrates the bug here:
https://gitlab.freedesktop.org/nroberts/igt-gpu-tools/-/commits/panfrost-pur...
Neil Roberts (2): drm/shmem-helper: Check for purged buffers in fault handler drm/shmem-helper: Don't remove the offset in vm_area_struct pgoff
drivers/gpu/drm/drm_gem_shmem_helper.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-)