diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index df916738fbd8..2df679d75454 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -902,8 +902,9 @@ debug_entry_t *debug_event_common(debug_info_t *id, int level, const void *buf,
 	}
 	do {
 		active = get_active_entry(id);
-		memset(DEBUG_DATA(active), 0, id->buf_size);
 		memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
+		if (len < id->buf_size)
+			memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 		debug_finish_entry(id, active, level, 0);
 		len -= id->buf_size;
 		buf += id->buf_size;
@@ -934,8 +935,9 @@ debug_entry_t *debug_exception_common(debug_info_t *id, int level,
 	}
 	do {
 		active = get_active_entry(id);
-		memset(DEBUG_DATA(active), 0, id->buf_size);
 		memcpy(DEBUG_DATA(active), buf, min(len, id->buf_size));
+		if (len < id->buf_size)
+			memset((DEBUG_DATA(active)) + len, 0, id->buf_size - len);
 		debug_finish_entry(id, active, level, len <= id->buf_size);
 		len -= id->buf_size;
 		buf += id->buf_size;