linux-kernel - Re: [PATCH v2 0/6] gpio: cdev: bail out of poll() if the device goes down

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAMRc=MfZ=GgcqKkDXkUgWC-bdCJECs0HfjRe9Ffy-Metwz6fFQ@mail.gmail.com>
Date:   Fri, 18 Aug 2023 14:06:21 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Kent Gibson <warthog618@...il.com>, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH v2 0/6] gpio: cdev: bail out of poll() if the device goes down

On Fri, Aug 18, 2023 at 12:34 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Thu, Aug 17, 2023 at 08:49:52PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> >
> > Wake up all three wake queues (the one associated with the character
> > device file, the one for V1 line events and the V2 line request one)
> > when the underlying GPIO device is unregistered. This way we won't get
> > stuck in poll() after the chip is gone as user-space will be forced to
> > go back into a new system call and will see that gdev->chip is NULL.
>
> Why can't you use the global device unbind notifications and filter out
> what you are interested in?
>

There's no truly global device unbind notification - only per-bus.
GPIO devices can reside on any bus, there are no limitations and so
we'd have to subscribe to all of them.

Bart