[3.11.y.z extended stable] Patch "[media] av7110_hw: Don't use dynamic static allocation" has been added to staging queue

[Luis Henriques]

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

    [media] av7110_hw: Don't use dynamic static allocation

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

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

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 46ddef0a84d38d85954b0773f2736e169411f96d Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <m.chehab at samsung.com>
Date: Sat, 2 Nov 2013 05:51:59 -0300
Subject: [media] av7110_hw: Don't use dynamic static allocation

commit 5bf30b3bc4ff80ef71a733a1f459cca4fa507892 upstream.

Dynamic static allocation is evil, as Kernel stack is too low, and
compilation complains about it on some archs:
	drivers/media/pci/ttpci/av7110_hw.c:510:1: warning: 'av7110_fw_cmd' uses dynamic stack allocation [enabled by default]
Instead, let's enforce a limit for the buffer.
In the specific case of this driver, the maximum fw command size
is 6 + 2, as checked using:
	$ git grep -A1 av7110_fw_cmd drivers/media/pci/ttpci/
So, use 8 for the buffer size.

Signed-off-by: Mauro Carvalho Chehab <m.chehab at samsung.com>
Reviewed-by: Hans Verkuil <hans.verkuil at cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab at samsung.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/media/pci/ttpci/av7110_hw.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/media/pci/ttpci/av7110_hw.c b/drivers/media/pci/ttpci/av7110_hw.c
index f1cbfe5..6299d5d 100644
--- a/drivers/media/pci/ttpci/av7110_hw.c
+++ b/drivers/media/pci/ttpci/av7110_hw.c
@@ -22,7 +22,7 @@
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  * Or, point your browser to http://www.gnu.org/copyleft/gpl.html
  *
- * the project's page is at http://www.linuxtv.org/
+ * the project's page is at http://www.linuxtv.org/
  */

 /* for debugging ARM communication: */
@@ -40,6 +40,14 @@

 #define _NOHANDSHAKE

+/*
+ * Max transfer size done by av7110_fw_cmd()
+ *
+ * The maximum size passed to this function is 6 bytes. The buffer also
+ * uses two additional ones for type and size. So, 8 bytes is enough.
+ */
+#define MAX_XFER_SIZE  8
+
 /****************************************************************************
  * DEBI functions
  ****************************************************************************/
@@ -488,11 +496,18 @@ static int av7110_send_fw_cmd(struct av7110 *av7110, u16* buf, int length)
 int av7110_fw_cmd(struct av7110 *av7110, int type, int com, int num, ...)
 {
 	va_list args;
-	u16 buf[num + 2];
+	u16 buf[MAX_XFER_SIZE];
 	int i, ret;

 //	dprintk(4, "%p\n", av7110);

+	if (2 + num > sizeof(buf)) {
+		printk(KERN_WARNING
+		       "%s: %s len=%d is too big!\n",
+		       KBUILD_MODNAME, __func__, num);
+		return -EINVAL;
+	}
+
 	buf[0] = ((type << 8) | com);
 	buf[1] = num;

--
1.8.3.2