1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c
index b5b335c9b2bb..2ebdc6d5a76e 100644
--- a/drivers/gpu/drm/udl/udl_fb.c
+++ b/drivers/gpu/drm/udl/udl_fb.c
@@ -159,10 +159,15 @@ static int udl_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
         unsigned long start = vma->vm_start;
         unsigned long size = vma->vm_end - vma->vm_start;
-        unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+        unsigned long offset;
         unsigned long page, pos;
 
-        if (offset + size > info->fix.smem_len)
+        if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
+                return -EINVAL;
+
+        offset = vma->vm_pgoff << PAGE_SHIFT;
+
+        if (offset > info->fix.smem_len || size > info->fix.smem_len - offset)
                 return -EINVAL;
 
         pos = (unsigned long)info->fix.smem_start + offset;