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

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 <[email protected]> know about it.

From: Arnd Bergmann <[email protected]>
Date: Thu, 2 Feb 2017 12:53:04 -0200
Subject: [media] pvrusb2: reduce stack usage pvr2_eeprom_analyze()

From: Arnd Bergmann <[email protected]>

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.

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

@@ -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 [email protected] are

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