diff --git a/src/basic/alloc-util.h b/src/basic/alloc-util.h
index cffc737d03a..64d9e00315e 100644
--- a/src/basic/alloc-util.h
+++ b/src/basic/alloc-util.h
@@ -58,7 +58,7 @@ static inline void *mfree(void *memory) {
         })
 
 void* memdup(const void *p, size_t l) _alloc_(2);
-void* memdup_suffix0(const void *p, size_t l) _alloc_(2);
+void* memdup_suffix0(const void *p, size_t l); /* We can't use _alloc_() here, since we return a buffer one byte larger than the specified size */
 
 #define memdupa(p, l)                           \
         ({                                      \