diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2f91bc8..92f6800 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -518,6 +518,11 @@ static XLogCtlData *XLogCtl = NULL;
 static ControlFileData *ControlFile = NULL;
 
 /*
+ * Local bufferspace for use in XLOG_HINT records.
+ */
+char *HintBuffer;
+
+/*
  * Macros for managing XLogInsert state.  In most cases, the calling routine
  * has local copies of XLogCtl->Insert and/or XLogCtl->Insert->curridx,
  * so these are passed as parameters instead of being fetched via XLogCtl.
@@ -880,7 +885,10 @@ begin:;
 		info |= XLR_BKP_BLOCK(i);
 
 		bkpb = &(dtbuf_xlg[i]);
-		page = (char *) BufferGetBlock(dtbuf[i]);
+		if (isHint)
+			page = (char *) HintBuffer;
+		else
+			page = (char *) BufferGetBlock(dtbuf[i]);
 
 		rdt->next = &(dtbuf_rdt1[i]);
 		rdt = rdt->next;
@@ -7663,6 +7671,19 @@ XLogSaveBufferForHint(Buffer buffer)
 	int			watermark = XLOG_HINT_WATERMARK;
 
 	/*
+	 * Copy the buffer to a local area, so that we can calculate the WAL
+	 * CRC without worrying that we only have share lock on the buffer.
+	 */
+	if (HintBuffer == NULL)
+	{
+		HintBuffer = malloc(BLCKSZ);
+		if (HintBuffer == NULL)
+			elog(ERROR, "out of memory");
+		MemSet(HintBuffer, 0, BLCKSZ);
+	}
+	memcpy(HintBuffer, (char *) BufferGetBlock(buffer), BLCKSZ);
+
+	/*
 	 * Not allowed to have zero-length records, so use a small watermark
 	 */
 	rdata[0].data = (char *) (&watermark);