Add a simple check to reject any size not aligned to the min_page_size. when size is not aligned to min_page_size, driver module should handle in their own way either to round_up() the size value to min_page_size or just to enable WARN_ON(). If we dont handle the alignment properly, we may hit the following bug, Unigine Heaven has allocation requests for example required pages are 257 and alignment request is 256. To allocate the left over 1 page, continues the iteration to find the order value which is 0 and when it compares with min_order = 8, triggers the BUG_ON(order < min_order). v2: add more commit description v3: remove WARN_ON() Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx> Suggested-by: Matthew Auld <matthew.auld@xxxxxxxxx> --- drivers/gpu/drm/drm_buddy.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 72f52f293249..11bb59399471 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -665,6 +665,9 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm, if (start + size == end) return __drm_buddy_alloc_range(mm, start, size, blocks); + if (!IS_ALIGNED(size, min_page_size)) + return -EINVAL; + pages = size >> ilog2(mm->chunk_size); order = fls(pages) - 1; min_order = ilog2(min_page_size) - ilog2(mm->chunk_size); base-commit: 4dcdb745569d8eef8db09e24e8ff2e5dffc0664c -- 2.25.1
