diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 05b9c3f31456..bd5d91a31183 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -256,7 +256,7 @@ void __init mem_init(void)
 #endif
 
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
-	set_max_mapnr(max_pfn);
+	set_max_mapnr(max_low_pfn);
 
 	kasan_late_init();