On 10/19/26 10:41, Jiale Yao wrote: > drm_mm_init() rejects a zero-length allocation range with a BUG check. > Several DRM TTM users can derive a zero page count from device-provided > VRAM metadata and pass it to the range manager.
The BUG check is there to point out driver bugs which try to initialize a VRAM manager while no VRAM is installed. That is intended behavior and returning an error instead of running into a BUG() makes that intended behavior go away and eventually cause more problems down the road. So absolutely clear NAK to that. Regards, Christian. > > This series rejects empty ranges at the affected callers and adds a > defensive check in the common range manager. Patches 1 through 4 and > 6 validate the individual driver inputs. Patch 5 protects the shared > range-manager API against any remaining zero-page caller. > > The series was checked with scripts/checkpatch.pl for every code patch. > > Jiale Yao (6): > drm/vram-helper: reject empty VRAM ranges > drm/nouveau: reject empty VRAM ranges > drm/qxl: reject empty TTM memory ranges > drm/radeon: reject empty VRAM ranges > drm/ttm: reject empty range manager sizes > drm/vmwgfx: reject empty VRAM ranges > > drivers/gpu/drm/drm_gem_vram_helper.c | 3 +++ > drivers/gpu/drm/nouveau/nouveau_ttm.c | 3 +++ > drivers/gpu/drm/qxl/qxl_ttm.c | 3 +++ > drivers/gpu/drm/radeon/radeon_ttm.c | 3 +++ > drivers/gpu/drm/ttm/ttm_range_manager.c | 3 +++ > drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 4 ++++ > 6 files changed, 19 insertions(+) >
