--- src/pam_mount.c.orig	2010-02-04 22:38:13.952135654 -0600
+++ src/pam_mount.c	2010-02-04 22:42:24.996136619 -0600
@@ -457,7 +457,9 @@
 		ret = pam_set_data(pamh, "pam_mount_system_authtok",
 		      authtok, clean_system_authtok);
 		if (ret == PAM_SUCCESS) {
-			if (mlock(authtok, strlen(authtok) + 1) < 0)
+			if (authtok == NULL)
+				w4rn("authtok is NULL in session code\n");
+			else if (mlock(authtok, strlen(authtok) + 1) < 0)
 				w4rn("mlock authtok: %s\n", strerror(errno));
 		} else {
 			l0g("error trying to save authtok for session code\n");