diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index b573185122fda459b4c4a0ebe045a7176f24c462..f9d6609d44ffd41725509cace945ad21733dd8b3 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -1262,8 +1262,23 @@ begin:;
 		xlog_outrec(&buf, rechdr);
 		if (rdata->data != NULL)
 		{
+			StringInfoData recordbuf;
+
+			/*
+			 * We have to piece together the WAL record data from the
+			 * XLogRecData entries, so that we can pass it to the rm_desc
+			 * function as one contiguous chunk. (but we can leave out any
+			 * extra entries we created for backup blocks)
+			 */
+			rdt_lastnormal->next = NULL;
+
+			initStringInfo(&recordbuf);
+			for (;rdata != NULL; rdata = rdata->next)
+				appendBinaryStringInfo(&recordbuf, rdata->data, rdata->len);
+
 			appendStringInfoString(&buf, " - ");
-			RmgrTable[rechdr->xl_rmid].rm_desc(&buf, rechdr->xl_info, rdata->data);
+			RmgrTable[rechdr->xl_rmid].rm_desc(&buf, rechdr->xl_info, recordbuf.data);
+			pfree(recordbuf.data);
 		}
 		elog(LOG, "%s", buf.data);
 		pfree(buf.data);