[2.6 patch] drivers/char/watchdog/pcwd_usb.c: fix a NULL pointer dereference

[2.6 patch] drivers/char/watchdog/pcwd_usb.c: fix a NULL pointer dereference

[Adrian Bunk]

The Coverity checker noted that this resulted in a NULL pointer 
reference if we were coming from

        if (usb_pcwd == NULL) {
                printk(KERN_ERR PFX "Out of memory\n");
                goto error;
        }


Signed-off-by: Adrian Bunk <bunk@stusta.de>

--- linux-2.6.16-rc5-mm3-full/drivers/char/watchdog/pcwd_usb.c.old	2006-03-10 18:18:00.000000000 +0100
+++ linux-2.6.16-rc5-mm3-full/drivers/char/watchdog/pcwd_usb.c	2006-03-10 18:18:45.000000000 +0100
@@ -705,7 +705,8 @@ err_out_misc_deregister:
 err_out_unregister_reboot:
 	unregister_reboot_notifier(&usb_pcwd_notifier);
 error:
-	usb_pcwd_delete (usb_pcwd);
+	if (usb_pcwd)
+		usb_pcwd_delete(usb_pcwd);
 	usb_pcwd_device = NULL;
 	return retval;
 }

Re: [2.6 patch] drivers/char/watchdog/pcwd_usb.c: fix a NULL pointer dereference

[Wim Van Sebroeck]

Hi Adrian,

> The Coverity checker noted that this resulted in a NULL pointer 
> reference if we were coming from
> 
>         if (usb_pcwd == NULL) {
>                 printk(KERN_ERR PFX "Out of memory\n");
>                 goto error;
>         }
> 
> 
> Signed-off-by: Adrian Bunk <bunk@stusta.de>

This is indeed a bug. I added this patch into my linux-2.6-watchdog-mm tree and I have tested it positively with a PCWD-USB card.

Thanks,
Wim.