Re: [PATCH 3/4] pinctrl: Add checks for empty names inpinmux_search_function

From: Tony Lindgren
Date: Fri Jan 20 2012 - 12:42:03 EST


* Stephen Warren <swarren@xxxxxxxxxx> [120120 08:28]:
> Tony Lindgren wrote at Friday, January 20, 2012 9:18 AM:
> > Otherwise we can get the following when dealing with
> > buggy data in a pinmux driver:
> >
> > Unable to handle kernel NULL pointer dereference at virtual address 00000000
>
> > diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
> > index 06b8943..ffe633d 100644
> > --- a/drivers/pinctrl/pinmux.c
> > +++ b/drivers/pinctrl/pinmux.c
> > @@ -584,6 +584,13 @@ static int pinmux_search_function(struct pinctrl_dev *pctldev,
> > selector);
> > int ret;
> >
> > + if (!fname) {
> > + pr_warning("no name for function%i\n",
> > + selector);
> > + selector++;
> > + continue;
> > + }
> > +
> > if (!strcmp(map->function, fname)) {
> > /* Found the function, check pin group */
> > ret = pinmux_check_pin_group(pctldev, selector,
>
> Shouldn't this be BUG_ON(!fname)?
>
> There are lots of other places that pmxops->get_function_name() is
> called. Wouldn't it be better to enhance e.g. pinmux_check_ops() to
> validate that all functions have a name during pinctrl registration?

Maybe yeah. I'll take a look next week when I'm back home.

Tony
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