diff --git a/[refs] b/[refs]
index 5d1538b5874c..3dbbcaab89b6 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e556bbbd9d2ff2b158915945ac82e2ac7def4d2f
+refs/heads/master: 303fa9e39605c1d56971dd22cd04d2186dc42c98
diff --git a/trunk/drivers/s390/cio/cio_debug.h b/trunk/drivers/s390/cio/cio_debug.h
index f88844adae1b..c9bf8989930f 100644
--- a/trunk/drivers/s390/cio/cio_debug.h
+++ b/trunk/drivers/s390/cio/cio_debug.h
@@ -23,6 +23,8 @@ extern debug_info_t *cio_debug_crw_id;
 static inline void
 CIO_HEX_EVENT(int level, void *data, int length)
 {
+	if (unlikely(!cio_debug_trace_id))
+		return;
 	while (length > 0) {
 		debug_event(cio_debug_trace_id, level, data, length);
 		length -= cio_debug_trace_id->buf_size;