Computing the clip rectangle is prone to off-by-one errors when writes happen near the end of a memory page. Point the end of the memory area to the first trailing byte, so that (end - start) returns the area's length.
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Javier Martinez Canillas javierm@redhat.com --- drivers/gpu/drm/drm_fb_helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index f15127a32f7a..a37fb4a980c8 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -699,7 +699,7 @@ void drm_fb_helper_deferred_io(struct fb_info *info, max = 0; list_for_each_entry(page, pagelist, lru) { start = page->index << PAGE_SHIFT; - end = start + PAGE_SIZE - 1; + end = start + PAGE_SIZE; min = min(min, start); max = max(max, end); }