drm/i915: Allow NULL memory region

Prevent a NULL pointer access in intel_memory_regions_hw_probe.

Fixes: 05da7d9f717b ("drm/i915/gem: Downgrade stolen lmem setup warning")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11704
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240712214156.3969584-1-jonathan.cavitt@intel.com
(cherry picked from commit d75dec1fcbcb05b021c08b62551649567ab8955c)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>

diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c
index 172dfa7c3588be0c850da824e139cc1215c8730b..d40ee1b42110a336df00f18cc957cde93fea2582 100644 (file)
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -368,8 +368,10 @@ int intel_memory_regions_hw_probe(struct drm_i915_private *i915)
                        goto out_cleanup;
                }
 
-               mem->id = i;
-               i915->mm.regions[i] = mem;
+               if (mem) { /* Skip on non-fatal errors */
+                       mem->id = i;
+                       i915->mm.regions[i] = mem;
+               }
        }
 
        for (i = 0; i < ARRAY_SIZE(i915->mm.regions); i++) {