Patch "[media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()" has been added to the 4.9-stable tree

Patch "[media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pvrusb2-reduce-stack-usage-pvr2_eeprom_analyze.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6830733d53a4517588e56227b9c8538633f0c496 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Thu, 2 Feb 2017 12:53:04 -0200
Subject: [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

From: Arnd Bergmann <arnd@arndb.de>

commit 6830733d53a4517588e56227b9c8538633f0c496 upstream.

The driver uses a relatively large data structure on the stack, which
showed up on my radar as we get a warning with the "latent entropy"
GCC plugin:

drivers/media/usb/pvrusb2/pvrusb2-eeprom.c:153:1: error: the frame size of 1376 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]

The warning is usually hidden as we raise the warning limit to 2048
when the plugin is enabled, but I'd like to lower that again in the
future, and making this function smaller helps to do that without
build regressions.

Further analysis shows that putting an 'i2c_client' structure on
the stack is not really supported, as the embedded 'struct device'
is not initialized here, and we are only saved by the fact that
the function that is called here does not use the pointer at all.

Fixes: d855497edbfb ("V4L/DVB (4228a): pvrusb2 to kernel 2.6.18")

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/media/usb/pvrusb2/pvrusb2-eeprom.c |   11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

--- a/drivers/media/usb/pvrusb2/pvrusb2-eeprom.c
+++ b/drivers/media/usb/pvrusb2/pvrusb2-eeprom.c
@@ -123,15 +123,10 @@ int pvr2_eeprom_analyze(struct pvr2_hdw
 	memset(&tvdata,0,sizeof(tvdata));
 
 	eeprom = pvr2_eeprom_fetch(hdw);
-	if (!eeprom) return -EINVAL;
+	if (!eeprom)
+		return -EINVAL;
 
-	{
-		struct i2c_client fake_client;
-		/* Newer version expects a useless client interface */
-		fake_client.addr = hdw->eeprom_addr;
-		fake_client.adapter = &hdw->i2c_adap;
-		tveeprom_hauppauge_analog(&fake_client,&tvdata,eeprom);
-	}
+	tveeprom_hauppauge_analog(NULL, &tvdata, eeprom);
 
 	trace_eeprom("eeprom assumed v4l tveeprom module");
 	trace_eeprom("eeprom direct call results:");


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.9/ila_xlat-add-missing-hash-secret-initialization.patch
queue-4.9/pvrusb2-reduce-stack-usage-pvr2_eeprom_analyze.patch