[Add] add xv6-rv

lasoft/xv6-la/user/zombie.c

@@ -0,0 +1,14 @@
+// Create a zombie process that
+// must be reparented at exit.
+
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+int
+main(void)
+{
+  if(fork() > 0)
+    sleep(5);  // Let child exit before parent.
+  exit(0);
+}