[PATCH 0/2] Fix purging buffers in the shmem helpers

[Neil Roberts]

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-purgemap/

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(-)

-- 
2.29.2