diff --git a/[refs] b/[refs]
index 898022beefb0..c920f9a99e6c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2e85d67690cf3ea3f074a6e872f675226883fe7f
+refs/heads/master: f39479363e0361c8bb4397481c01a7c3a1a3c8ac
diff --git a/trunk/drivers/isdn/i4l/isdn_tty.c b/trunk/drivers/isdn/i4l/isdn_tty.c
index d8a7d8323414..ebaebdf30f98 100644
--- a/trunk/drivers/isdn/i4l/isdn_tty.c
+++ b/trunk/drivers/isdn/i4l/isdn_tty.c
@@ -902,7 +902,9 @@ isdn_tty_send_msg(modem_info *info, atemu *m, char *msg)
 	int j;
 	int l;
 
-	l = strlen(msg);
+	l = min(strlen(msg), sizeof(cmd.parm) - sizeof(cmd.parm.cmsg)
+		+ sizeof(cmd.parm.cmsg.para) - 2);
+
 	if (!l) {
 		isdn_tty_modem_result(RESULT_ERROR, info);
 		return;