From 5f77876013d08fe9d43bb4b7f9f7a81e4d3b63a9 Mon Sep 17 00:00:00 2001 From: Arunpravin Paneer Selvam Date: Mon, 11 Apr 2022 13:08:34 +0530 Subject: [PATCH] drm: add a check to verify the size alignment MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Suggested-by: Matthew Auld Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20220411073834.15210-1-Arunpravin.PaneerSelvam@amd.com Signed-off-by: Christian König --- 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 72f52f2..11bb593 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); -- 2.7.4