Re: [PATCH] pinctrl: bcm2835: Fix a few error paths

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Fri, Jan 28, 2022 at 08:12:02AM -0800, Florian Fainelli wrote:
> On 1/28/2022 6:35 AM, Andy Shevchenko wrote:
> > On Thu, Jan 27, 2022 at 01:50:31PM -0800, Florian Fainelli wrote:
> > > After commit 266423e60ea1 ("pinctrl: bcm2835: Change init order for gpio
> > > hogs") a few error paths would not unwind properly the registration of
> > > gpio ranges. Correct that by assigning a single error label and goto it
> > > whenever we encounter a fatal error.
> > 
> > >   1 file changed, 15 insertions(+), 8 deletions(-)
> > 
> > While this seems legit per se, my eyes caught this:
> > 
> > 
> > >   	if (!girq->parents) {
> > > -		pinctrl_remove_gpio_range(pc->pctl_dev, &pc->gpio_range);
> > > -		return -ENOMEM;
> > > +		err = -ENOMEM;
> > > +		goto out_remove;
> > 
> > Non-devm....
> > 
> > >   	}
> > >   	if (is_7211) {
> > >   		pc->wake_irq = devm_kcalloc(dev, BCM2835_NUM_IRQS,
> > >   					    sizeof(*pc->wake_irq),
> > >   					    GFP_KERNEL);
> > 
> > ...followed by devm.
> > 
> > It means more ordering bugs in the ->remove() and error path are lurking
> > around. Can you double check and be sure that we do not have a case where
> > non-devm registration code followed by devm?
> 
> It seems to me like we are fine with the patch as is, because:
> 
> - girq->parents is allocated with devm
> - pc->wake_irq is allocated with devm
> - name is allocated with devm
> 
> and those are the only variables being allocated for which we also process
> an error handling path.

Okay, thanks.

My worries that it might be the case when the GPIO ranges have been removed by
explicit call in ->remove() followed by some interrupt or so and oops or
misbehaviour because of that.

-- 
With Best Regards,
Andy Shevchenko