linux-kernel - [PATCH] radio-si470x.c: check-after-use

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Date:	Mon, 28 Jan 2008 23:43:13 +0100
From:	Tobias Lorenz <tobias.lorenz@....net>
To:	Mauro Carvalho Chehab <mchehab@...radead.org>
Cc:	Adrian Bunk <bunk@...nel.org>, video4linux-list@...hat.com,
	linux-kernel@...r.kernel.org
Subject: [PATCH] radio-si470x.c: check-after-use

Hi Mauro,
Hi Adrian,

Adrian used the coverity checker against radio-si470x and found this:

> The Coverity checker spotted the following check-after-use in 
> drivers/media/radio/radio-si470x.c:
> 
> <--  snip  -->
> static void si470x_usb_driver_disconnect(struct usb_interface *intf)
> {
>         struct si470x_device *radio = usb_get_intfdata(intf);
> 
>         del_timer_sync(&radio->timer);    <------------------
>         flush_scheduled_work();
> 
>         usb_set_intfdata(intf, NULL);
>         if (radio) {                      <------------------
>                 video_unregister_device(radio->videodev);
>                 kfree(radio->buffer);
>                 kfree(radio);
>         }
> }
> <--  snip  -->
> 
> Either "radio" can be NULL and this case has to be properly handled or 
> the NULL check is not required.

These two lines should indeed better be inside the if statement. The patch for this is below.

Thanks,
  Toby

Signed-off-by: Tobias Lorenz <tobias.lorenz@....net>
--- linux-2.6.23/drivers/media/radio/radio-si470x.c     2008-01-23 00:01:07.000000000 +0100
+++ linux-2.6.23.new/drivers/media/radio/radio-si470x.c 2008-01-27 15:31:42.000000000 +0100
@@ -1440,11 +1440,10 @@ static void si470x_usb_driver_disconnect
 {
        struct si470x_device *radio = usb_get_intfdata(intf);

-       del_timer_sync(&radio->timer);
-       flush_scheduled_work();
-
        usb_set_intfdata(intf, NULL);
        if (radio) {
+               del_timer_sync(&radio->timer);
+               flush_scheduled_work();
                video_unregister_device(radio->videodev);
                kfree(radio->buffer);
                kfree(radio);
--
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