linux-kernel - Re: [PATCH 1/2] gpio: em: remove the gpiochip before removing the irq domain

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Date:   Wed, 10 Jul 2019 11:47:18 +0200
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Phil Reid <preid@...ctromag.com.au>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        linux-gpio <linux-gpio@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "Stable # 4 . 20+" <stable@...r.kernel.org>
Subject: Re: [PATCH 1/2] gpio: em: remove the gpiochip before removing the irq domain

śr., 10 lip 2019 o 11:37 Phil Reid <preid@...ctromag.com.au> napisał(a):
>
> G'day Bartosz,
>
> One comment below
>
> On 10/07/2019 17:08, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> >
> > In commit 8764c4ca5049 ("gpio: em: use the managed version of
> > gpiochip_add_data()") we implicitly altered the ordering of resource
> > freeing: since gpiochip_remove() calls gpiochip_irqchip_remove()
> > internally, we now can potentially use the irq_domain after it was
> > destroyed in the remove() callback (as devm resources are freed after
> > remove() has returned).
> >
> > Use devm_add_action() to keep the ordering right and entirely kill
> > the remove() callback in the driver.
> >
> > Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> > Fixes: 8764c4ca5049 ("gpio: em: use the managed version of gpiochip_add_data()")
> > Cc: stable@...r.kernel.org
> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > ---
> >   drivers/gpio/gpio-em.c | 35 +++++++++++++++++------------------
> >   1 file changed, 17 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/gpio/gpio-em.c b/drivers/gpio/gpio-em.c
> > index b6af705a4e5f..c88028ac66f2 100644
> > --- a/drivers/gpio/gpio-em.c
> > +++ b/drivers/gpio/gpio-em.c
> > @@ -259,6 +259,13 @@ static const struct irq_domain_ops em_gio_irq_domain_ops = {
> >       .xlate  = irq_domain_xlate_twocell,
> >   };
> >
> > +static void em_gio_irq_domain_remove(void *data)
> > +{
> > +     struct irq_domain *domain = data;
> > +
> > +     irq_domain_remove(domain);
> > +}
> > +
> >   static int em_gio_probe(struct platform_device *pdev)
> >   {
> >       struct em_gio_priv *p;
> > @@ -333,39 +340,32 @@ static int em_gio_probe(struct platform_device *pdev)
> >               return -ENXIO;
> >       }
> >
> > +     ret = devm_add_action(&pdev->dev,
> > +                           em_gio_irq_domain_remove, p->irq_domain);
>
> Could devm_add_action_or_reset be used?
>

Of course it could and it should. :)

I'll resend tomorrow to not spam the mailing list.

Thanks,
Bart

> > +     if (ret) {
> > +             irq_domain_remove(p->irq_domain);
> > +             return ret;
> > +     }
> > +
> >       if (devm_request_irq(&pdev->dev, irq[0]->start,
> >                            em_gio_irq_handler, 0, name, p)) {
> >               dev_err(&pdev->dev, "failed to request low IRQ\n");
> > -             ret = -ENOENT;
> > -             goto err1;
> > +             return -ENOENT;
> >       }
> >
> >       if (devm_request_irq(&pdev->dev, irq[1]->start,
> >                            em_gio_irq_handler, 0, name, p)) {
> >               dev_err(&pdev->dev, "failed to request high IRQ\n");
> > -             ret = -ENOENT;
> > -             goto err1;
> > +             return -ENOENT;
> >       }
> >
> >       ret = devm_gpiochip_add_data(&pdev->dev, gpio_chip, p);
> >       if (ret) {
> >               dev_err(&pdev->dev, "failed to add GPIO controller\n");
> > -             goto err1;
> > +             return ret;
> >       }
> >
> >       return 0;
> > -
> > -err1:
> > -     irq_domain_remove(p->irq_domain);
> > -     return ret;
> > -}
> > -
> > -static int em_gio_remove(struct platform_device *pdev)
> > -{
> > -     struct em_gio_priv *p = platform_get_drvdata(pdev);
> > -
> > -     irq_domain_remove(p->irq_domain);
> > -     return 0;
> >   }
> >
> >   static const struct of_device_id em_gio_dt_ids[] = {
> > @@ -376,7 +376,6 @@ MODULE_DEVICE_TABLE(of, em_gio_dt_ids);
> >
> >   static struct platform_driver em_gio_device_driver = {
> >       .probe          = em_gio_probe,
> > -     .remove         = em_gio_remove,
> >       .driver         = {
> >               .name   = "em_gio",
> >               .of_match_table = em_gio_dt_ids,
> >
>
>
> --
> Regards
> Phil Reid
>