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@xxxxxxx>
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---
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);
}
--
2.34.1
