Re: [PATCH] 3c507.c: remove unused NULL pointer check

Oliver Hartkopp
2009-12-21T16:56:45Z

Alexander Strakh wrote:
> 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 (Svace detector)
>
> Remove unused NULL pointer check.

You are obviously doing more than that ...

>
> Signed-off-by: Alexander Strakh <strakh@ispras.ru>
>
> ---
> diff --git a/./0000/drivers/net/3c507.c b/./moder/drivers/net/3c507.c
> index fbc2311..3bfb3dd 100644
> --- a/./0000/drivers/net/3c507.c
> +++ b/./moder/drivers/net/3c507.c
> @@ -552,12 +552,6 @@ static irqreturn_t el16_interrupt(int irq, void *dev_id)
> ushort ack_cmd = 0;
> void __iomem *shmem;
>
> - if (dev == NULL) {
> - pr_err("%s: net_interrupt(): irq %d for unknown device.\n",
> - dev->name, irq);

You are changing real funcionality here!

If you want to fix it, fix the pr_err() but do not remove the "return
IRQ_NONE" entirely.

This looks like an introduction of a bug.

Regards,
Oliver

> - return IRQ_NONE;
> - }
> -