linux-kernel - Re: [PATCH] gpiolib: don't call sleeping functions with a spinlock taken

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Date:   Thu, 16 Apr 2020 13:19:33 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc:     Bartosz Golaszewski <brgl@...ev.pl>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpiolib: don't call sleeping functions with a spinlock taken

On Tue, Apr 14, 2020 at 2:27 PM Bartosz Golaszewski
<bgolaszewski@...libre.com> wrote:
> wt., 14 kwi 2020 o 14:00 Linus Walleij <linus.walleij@...aro.org> napisał(a):
> >
> > On Fri, Mar 20, 2020 at 10:31 AM Bartosz Golaszewski <brgl@...ev.pl> wrote:
> >
> > > From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> > >
> > > We must not call pinctrl_gpio_can_use_line() with the gpio_lock taken
> > > as it takes a mutex internally. Let's move the call before taking the
> > > spinlock and store the return value.
> > >
> > > This isn't perfect - there's a moment between calling
> > > pinctrl_gpio_can_use_line() and taking the spinlock where the situation
> > > can change but it isn't a regression either: previously this part wasn't
> > > protected at all and it only affects the information user-space is
> > > seeing.
> > >
> > > Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> > > Fixes: d2ac25798208 ("gpiolib: provide a dedicated function for setting lineinfo")
> > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> >
> > I'm sorry that I lost track of this patch :(
> >
> > Do we still need something like this or has it been fixed
> > by some other patches?
> >
> > Yours,
> > Linus Walleij
>
> Nope, this is still an issue. Do you have a better idea than mine?

Nope, can you just queue it in your tree?
Acked-by: Linus Walleij <linus.walleij@...aro.org>

Yours,
Linus Walleij