Re: BUG null dereference in driver ./drivers/net/3c507.c

Re: BUG null dereference in driver ./drivers/net/3c507.c

[Bartlomiej Zolnierkiewicz]

Hi,

On Tuesday 15 December 2009 06:55:08 pm Alexander Strakh wrote:
> 	KERNEL_VERSION: 2.6.32
> 	SUBJECT: null dereference aftre check
> 	DESCRIBE:
> 	In driver drivers/net/3c507.c in function Iirqreturn_t el16_interrupt:
> 
> 1. If in line 555 dev = NULL then we goto line 556
> 2. In line 556 we have null dereference because pr_err called with dev->name 
> in third parameter.
> 
>  555        if (dev == NULL) {
>  556                pr_err("%s: net_interrupt(): irq %d for unknown device.
> \n",
>  557                        dev->name, irq);
>  558                return IRQ_NONE;
>  559        }

There is no NULL dereference bug there possible since 'dev' will never be
actually NULL in el16_interrupt() (because of the way IRQ kernel subsystem
and 3c507 network driver are designed/work).

IOW it is just a bogus NULL pointer check, though it still would be nice
to have the issue fixed.  Care to send a patch removing it?

--
Bartlomiej Zolnierkiewicz

BUG null dereference in driver ./drivers/net/3c507.c

[Alexander Strakh]

	KERNEL_VERSION: 2.6.32
	SUBJECT: null dereference aftre check
	DESCRIBE:
	In driver drivers/net/3c507.c in function Iirqreturn_t el16_interrupt:

1. If in line 555 dev = NULL then we goto line 556
2. In line 556 we have null dereference because pr_err called with dev->name 
in third parameter.

 555        if (dev == NULL) {
 556                pr_err("%s: net_interrupt(): irq %d for unknown device.
\n",
 557                        dev->name, irq);
 558                return IRQ_NONE;
 559        }

Found by Linux Device Drivers Verification Project (Svace Detector)