diff --git a/gst/matroska/ebml-write.c b/gst/matroska/ebml-write.c
index 4596c2f200..d39a23adbf 100644
--- a/gst/matroska/ebml-write.c
+++ b/gst/matroska/ebml-write.c
@@ -427,7 +427,10 @@ gst_ebml_write_element_push (GstEbmlWrite * ebml, GstBuffer * buf,
       gst_buffer_map (buf, &map, GST_MAP_READ);
       buf_data = map.data;
     }
-    if (!gst_byte_writer_put_data (ebml->streamheader, buf_data, data_size))
+    if (!buf_data)
+      GST_WARNING ("Failed to map buffer");
+    else if (!gst_byte_writer_put_data (ebml->streamheader, buf_data,
+            data_size))
       GST_WARNING ("Error writing data to streamheader");
   }
   if (ebml->cache) {
@@ -435,7 +438,9 @@ gst_ebml_write_element_push (GstEbmlWrite * ebml, GstBuffer * buf,
       gst_buffer_map (buf, &map, GST_MAP_READ);
       buf_data = map.data;
     }
-    if (!gst_byte_writer_put_data (ebml->cache, buf_data, data_size))
+    if (!buf_data)
+      GST_WARNING ("Failed to map buffer");
+    else if (!gst_byte_writer_put_data (ebml->cache, buf_data, data_size))
       GST_WARNING ("Error writing data to cache");
     if (map.data)
       gst_buffer_unmap (buf, &map);