fix_do_pg_abort_backup.patch

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 0513471..b0381e8 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -11165,8 +11165,15 @@ void
 do_pg_abort_backup(void)
 {
 	WALInsertLockAcquireExclusive();
-	Assert(XLogCtl->Insert.nonExclusiveBackups > 0);
-	XLogCtl->Insert.nonExclusiveBackups--;
+
+	/*
+	 * This can be called after we decremented nonExclusiveBackups in
+	 * do_pg_stop_backup. So prevent it to be negative value.
+	 */
+-	Assert(XLogCtl->Insert.nonExclusiveBackups >= 0);
+	if (XLogCtl->Insert.nonExclusiveBackups > 0)
+		XLogCtl->Insert.nonExclusiveBackups--;
+
 
 	if (XLogCtl->Insert.exclusiveBackupState == EXCLUSIVE_BACKUP_NONE &&
 		XLogCtl->Insert.nonExclusiveBackups == 0)