Index: sbin/mdmfs/mdmfs.c
===================================================================
--- sbin/mdmfs/mdmfs.c
+++ sbin/mdmfs/mdmfs.c
@@ -674,8 +674,12 @@
  * Run a process with command name and arguments pointed to by the
  * formatted string 'cmdline'.  Since system(3) is not used, the first
  * space-delimited token of 'cmdline' must be the full pathname of the
- * program to run.  The return value is the return code of the process
- * spawned.  If 'ofd' is non-NULL, it is set to the standard output of
+ * program to run.
+ *
+ * The return value is the return code of the process spawned, or a negative
+ * signal number, if the process exited due to an uncaught signal.
+ *
+ * If 'ofd' is non-NULL, it is set to the standard output of
  * the program spawned (i.e., you can read from ofd and get the output
  * of the program).
  */
@@ -771,7 +775,12 @@
 	free(argv);
 	while (waitpid(pid, &status, 0) != pid)
 		;
-	return (WEXITSTATUS(status));
+	if (WIFEXITED(status))
+		return (WEXITSTATUS(status));
+	else if (WIFSIGNALED(status))
+		return (-WTERMSIG(status));
+	else
+		err(1, "unexpected waitpid status: 0x%x", status);
 }
 
 static void