diff --git a/sys/kern/subr_asan.c b/sys/kern/subr_asan.c
--- a/sys/kern/subr_asan.c
+++ b/sys/kern/subr_asan.c
@@ -155,6 +155,8 @@
 		return "MallocRedZone";
 	case KASAN_KMEM_REDZONE:
 		return "KmemRedZone";
+	case KASAN_UMA_NEVERUSED:
+		return "UMANeverAllocated";
 	case KASAN_UMA_FREED:
 		return "UMAUseAfterFree";
 	case KASAN_KSTACK_FREED:
diff --git a/sys/sys/asan.h b/sys/sys/asan.h
--- a/sys/sys/asan.h
+++ b/sys/sys/asan.h
@@ -46,6 +46,7 @@
 #define KASAN_USE_AFTER_SCOPE	0xF8
 
 /* Our redzone values. */
+#define KASAN_UMA_NEVERUSED	0xF9
 #define KASAN_GENERIC_REDZONE	0xFA
 #define KASAN_MALLOC_REDZONE	0xFB
 #define KASAN_KMEM_REDZONE	0xFC
diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
--- a/sys/vm/uma_core.c
+++ b/sys/vm/uma_core.c
@@ -606,7 +606,7 @@
 			sz = keg->uk_ppera * PAGE_SIZE;
 		else
 			sz = keg->uk_pgoff;
-		kasan_mark(mem, 0, sz, KASAN_UMA_FREED);
+		kasan_mark(mem, 0, sz, KASAN_UMA_NEVERUSED);
 	}
 }
 #else /* !KASAN */