better locking
diff --git a/src/cmd/upas/common/libsys.c b/src/cmd/upas/common/libsys.c
index ced0003..8e55fc4 100644
--- a/src/cmd/upas/common/libsys.c
+++ b/src/cmd/upas/common/libsys.c
@@ -278,6 +278,7 @@
 			break;
 		case 'l':
 			sysperm |= DMEXCL;
+			sysmode |= OLOCK;
 			break;
 		case 'a':
 			sysperm |= DMAPPEND;