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

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Date:   Fri, 28 Jan 2022 08:12:02 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-kernel@...r.kernel.org,
        Linus Walleij <linus.walleij@...aro.org>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        "maintainer:BROADCOM BCM281XX/BCM11XXX/BCM216XX ARM ARCHITE..." 
        <bcm-kernel-feedback-list@...adcom.com>,
        Nicolas Saenz Julienne <nsaenz@...nel.org>,
        Phil Elwell <phil@...pberrypi.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Jason Wang <wangborong@...rlc.com>,
        Marc Zyngier <maz@...nel.org>,
        "open list:PIN CONTROL SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-rpi-kernel@...ts.infradead.org>,
        "moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] pinctrl: bcm2835: Fix a few error paths



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.
-- 
Florian