1 files changed, 16 insertions, 2 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index 0ceae57da7da..08b207f8e61e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -851,7 +851,12 @@ static int madvise_free_single_vma(struct vm_area_struct *vma,
 static long madvise_dontneed_single_vma(struct vm_area_struct *vma,
 					unsigned long start, unsigned long end)
 {
-	zap_page_range_single(vma, start, end - start, NULL);
+	struct zap_details details = {
+		.reclaim_pt = true,
+		.even_cows = true,
+	};
+
+	zap_page_range_single(vma, start, end - start, &details);
 	return 0;
 }
 
@@ -928,7 +933,16 @@ static long madvise_dontneed_free(struct vm_area_struct *vma,
 			 */
 			end = vma->vm_end;
 		}
-		VM_WARN_ON(start >= end);
+		/*
+		 * If the memory region between start and end was
+		 * originally backed by 4kB pages and then remapped to
+		 * be backed by hugepages while mmap_lock was dropped,
+		 * the adjustment for hugetlb vma above may have rounded
+		 * end down to the start address.
+		 */
+		if (start == end)
+			return 0;
+		VM_WARN_ON(start > end);
 	}
 
 	if (behavior == MADV_DONTNEED || behavior == MADV_DONTNEED_LOCKED)