[ 3.5.yuz extended stable ] Patch "USB: opticon: fix DMA from stack" has been added to staging queue

Herton Ronaldo Krzesinski herton.krzesinski at canonical.com
Thu Nov 22 04:49:40 UTC 2012

This is a note to let you know that I have just added a patch titled

    USB: opticon: fix DMA from stack

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.yuz tree, see



>From 176121548fabe2356fc0b0b2d9c9c95bb8ade469 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold at gmail.com>
Date: Thu, 25 Oct 2012 10:29:11 +0200
Subject: [PATCH] USB: opticon: fix DMA from stack

commit ea0dbebffe118724cd4df7d9b071ea8ee48d48f0 upstream.

Make sure to allocate the control-message buffer dynamically as some
platforms cannot do DMA from stack.

Note that only the first byte of the old buffer was used.

Signed-off-by: Johan Hovold <jhovold at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
 drivers/usb/serial/opticon.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 02cb1b7..5ba2700 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -158,7 +158,11 @@ static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
 	struct usb_serial *serial = port->serial;
 	int retval;
-	u8 buffer[2];
+	u8 *buffer;
+	buffer = kzalloc(1, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;

 	buffer[0] = val;
 	/* Send the message to the vendor control endpoint
@@ -167,6 +171,7 @@ static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
 				0, 0, buffer, 1, 0);
+	kfree(buffer);

 	return retval;

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