diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 62122bad1e33..400b040df7fa 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -604,13 +604,13 @@ setup_memory(void)
 		if (memory_chunk[i].type != CHUNK_READ_WRITE)
 			continue;
 		start_chunk = PFN_DOWN(memory_chunk[i].addr);
-		end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size) - 1;
+		end_chunk = start_chunk + PFN_DOWN(memory_chunk[i].size);
 		end_chunk = min(end_chunk, end_pfn);
 		if (start_chunk >= end_chunk)
 			continue;
 		add_active_range(0, start_chunk, end_chunk);
 		pfn = max(start_chunk, start_pfn);
-		for (; pfn <= end_chunk; pfn++)
+		for (; pfn < end_chunk; pfn++)
 			page_set_storage_key(PFN_PHYS(pfn), PAGE_DEFAULT_KEY);
 	}