[PATCH] gpio: tpmx86: fix uninitialized variable girq

[PATCH] gpio: tpmx86: fix uninitialized variable girq

[Dongliang Mu]

From: Dongliang Mu <mudongliangabcd@gmail.com>

The commit 924610607f19 ("gpio: tpmx86: Move PM device over to
irq domain") adds a dereference of girq that may be uninitialized.

Fix this by initializing girq and checking irq before invoking
irq_domain_set_pm_device.

Fixes: 924610607f19 ("gpio: tpmx86: Move PM device over to irq domain")
Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
---
 drivers/gpio/gpio-tqmx86.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
index fa4bc7481f9a..bdef182c11c2 100644
--- a/drivers/gpio/gpio-tqmx86.c
+++ b/drivers/gpio/gpio-tqmx86.c
@@ -231,7 +231,7 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct tqmx86_gpio_data *gpio;
 	struct gpio_chip *chip;
-	struct gpio_irq_chip *girq;
+	struct gpio_irq_chip *girq = NULL;
 	void __iomem *io_base;
 	struct resource *res;
 	int ret, irq;
@@ -315,7 +315,9 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
 		goto out_pm_dis;
 	}
 
-	irq_domain_set_pm_device(girq->domain, dev);
+	if (girq) {
+		irq_domain_set_pm_device(girq->domain, dev);
+	}
 
 	dev_info(dev, "GPIO functionality initialized with %d pins\n",
 		 chip->ngpio);
-- 
2.35.1

Re: [PATCH] gpio: tpmx86: fix uninitialized variable girq

[Marc Zyngier]

On Wed, 14 Sep 2022 06:18:42 +0100,
Dongliang Mu <dzm91@hust.edu.cn> wrote:
> 
> From: Dongliang Mu <mudongliangabcd@gmail.com>
> 
> The commit 924610607f19 ("gpio: tpmx86: Move PM device over to
> irq domain") adds a dereference of girq that may be uninitialized.
> 
> Fix this by initializing girq and checking irq before invoking
> irq_domain_set_pm_device.
> 
> Fixes: 924610607f19 ("gpio: tpmx86: Move PM device over to irq domain")
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>  drivers/gpio/gpio-tqmx86.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
> index fa4bc7481f9a..bdef182c11c2 100644
> --- a/drivers/gpio/gpio-tqmx86.c
> +++ b/drivers/gpio/gpio-tqmx86.c
> @@ -231,7 +231,7 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct tqmx86_gpio_data *gpio;
>  	struct gpio_chip *chip;
> -	struct gpio_irq_chip *girq;
> +	struct gpio_irq_chip *girq = NULL;
>  	void __iomem *io_base;
>  	struct resource *res;
>  	int ret, irq;
> @@ -315,7 +315,9 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
>  		goto out_pm_dis;
>  	}
>  
> -	irq_domain_set_pm_device(girq->domain, dev);
> +	if (girq) {
> +		irq_domain_set_pm_device(girq->domain, dev);
> +	}
>  
>  	dev_info(dev, "GPIO functionality initialized with %d pins\n",
>  		 chip->ngpio);

I wonder if a better fix wouldn't be to directly hoist the
irq_domain_set_pm_device() call into the 'if (irq > 0)' block.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

Re: [PATCH] gpio: tpmx86: fix uninitialized variable girq

[Dongliang Mu]

On Wed, Sep 14, 2022 at 3:36 PM Marc Zyngier <maz@kernel.org> wrote:
>
> On Wed, 14 Sep 2022 06:18:42 +0100,
> Dongliang Mu <dzm91@hust.edu.cn> wrote:
> >
> > From: Dongliang Mu <mudongliangabcd@gmail.com>
> >
> > The commit 924610607f19 ("gpio: tpmx86: Move PM device over to
> > irq domain") adds a dereference of girq that may be uninitialized.
> >
> > Fix this by initializing girq and checking irq before invoking
> > irq_domain_set_pm_device.
> >
> > Fixes: 924610607f19 ("gpio: tpmx86: Move PM device over to irq domain")
> > Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> > ---
> >  drivers/gpio/gpio-tqmx86.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
> > index fa4bc7481f9a..bdef182c11c2 100644
> > --- a/drivers/gpio/gpio-tqmx86.c
> > +++ b/drivers/gpio/gpio-tqmx86.c
> > @@ -231,7 +231,7 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
> >       struct device *dev = &pdev->dev;
> >       struct tqmx86_gpio_data *gpio;
> >       struct gpio_chip *chip;
> > -     struct gpio_irq_chip *girq;
> > +     struct gpio_irq_chip *girq = NULL;
> >       void __iomem *io_base;
> >       struct resource *res;
> >       int ret, irq;
> > @@ -315,7 +315,9 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
> >               goto out_pm_dis;
> >       }
> >
> > -     irq_domain_set_pm_device(girq->domain, dev);
> > +     if (girq) {
> > +             irq_domain_set_pm_device(girq->domain, dev);
> > +     }
> >
> >       dev_info(dev, "GPIO functionality initialized with %d pins\n",
> >                chip->ngpio);
>
> I wonder if a better fix wouldn't be to directly hoist the
> irq_domain_set_pm_device() call into the 'if (irq > 0)' block.

If irq_domain_set_pm_device has no dependency on
devm_gpiochip_add_data, we can directly move irq_domain_set_pm_device
to the if block.

>
> Thanks,
>
>         M.
>
> --
> Without deviation from the norm, progress is not possible.

Re: [PATCH] gpio: tpmx86: fix uninitialized variable girq

[Marc Zyngier]

On Thu, 15 Sep 2022 07:08:10 +0100,
Dongliang Mu <mudongliangabcd@gmail.com> wrote:
> 
> On Wed, Sep 14, 2022 at 3:36 PM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Wed, 14 Sep 2022 06:18:42 +0100,
> > Dongliang Mu <dzm91@hust.edu.cn> wrote:
> > >
> > > From: Dongliang Mu <mudongliangabcd@gmail.com>
> > >
> > > The commit 924610607f19 ("gpio: tpmx86: Move PM device over to
> > > irq domain") adds a dereference of girq that may be uninitialized.
> > >
> > > Fix this by initializing girq and checking irq before invoking
> > > irq_domain_set_pm_device.
> > >
> > > Fixes: 924610607f19 ("gpio: tpmx86: Move PM device over to irq domain")
> > > Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> > > ---
> > >  drivers/gpio/gpio-tqmx86.c | 6 ++++--
> > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpio/gpio-tqmx86.c b/drivers/gpio/gpio-tqmx86.c
> > > index fa4bc7481f9a..bdef182c11c2 100644
> > > --- a/drivers/gpio/gpio-tqmx86.c
> > > +++ b/drivers/gpio/gpio-tqmx86.c
> > > @@ -231,7 +231,7 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
> > >       struct device *dev = &pdev->dev;
> > >       struct tqmx86_gpio_data *gpio;
> > >       struct gpio_chip *chip;
> > > -     struct gpio_irq_chip *girq;
> > > +     struct gpio_irq_chip *girq = NULL;
> > >       void __iomem *io_base;
> > >       struct resource *res;
> > >       int ret, irq;
> > > @@ -315,7 +315,9 @@ static int tqmx86_gpio_probe(struct platform_device *pdev)
> > >               goto out_pm_dis;
> > >       }
> > >
> > > -     irq_domain_set_pm_device(girq->domain, dev);
> > > +     if (girq) {
> > > +             irq_domain_set_pm_device(girq->domain, dev);
> > > +     }
> > >
> > >       dev_info(dev, "GPIO functionality initialized with %d pins\n",
> > >                chip->ngpio);
> >
> > I wonder if a better fix wouldn't be to directly hoist the
> > irq_domain_set_pm_device() call into the 'if (irq > 0)' block.
> 
> If irq_domain_set_pm_device has no dependency on
> devm_gpiochip_add_data, we can directly move irq_domain_set_pm_device
> to the if block.

There is no dependency there, and you can convince yourself by looking
at the (trivial) code.

	M.

-- 
Without deviation from the norm, progress is not possible.