diff --git a/mm/slab.c b/mm/slab.c
index c7576b9..9d35500 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3541,7 +3541,7 @@
  *
  * Currently only used for dentry validation.
  */
-int fastcall kmem_ptr_validate(struct kmem_cache *cachep, void *ptr)
+int fastcall kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr)
 {
 	unsigned long addr = (unsigned long)ptr;
 	unsigned long min_addr = PAGE_OFFSET;
diff --git a/mm/slob.c b/mm/slob.c
index b90091c..2e9236e 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -334,7 +334,7 @@
 }
 EXPORT_SYMBOL(kmem_cache_shrink);
 
-int kmem_ptr_validate(struct kmem_cache *a, void *b)
+int kmem_ptr_validate(struct kmem_cache *a, const void *b)
 {
 	return 0;
 }