From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Kent Gibson <warthog618@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: Re: [PATCH] gpiolib: cdev: fix NULL-pointer dereferences
Date: Fri, 25 Nov 2022 19:56:09 +0200 [thread overview]
Message-ID: <Y4EBubusGqo4IroP@smile.fi.intel.com> (raw)
In-Reply-To: <CAMRc=Me83-_oiGEmwy4BUrzLEMT6ZsoMwWYsb6iXwg19yHMHdQ@mail.gmail.com>
On Fri, Nov 25, 2022 at 05:48:02PM +0100, Bartosz Golaszewski wrote:
> On Fri, Nov 25, 2022 at 5:24 PM Kent Gibson <warthog618@gmail.com> wrote:
...
> Then at the subsystem level, the GPIO device struct would need a lock
> that would be taken by every user-space operation AND the code
> unregistering the device so that we don't do what you described (i.e.
> if there's a thread doing a read(), then let's wait until it returns
> before we drop the device).
It's called a reference counting, basically you need to get device and then
put when it makes sense.
> This wouldn't fix the case in which the same situation happened in a
> kernel driver but crashing the kernel from within is a much lesser
> offense than allowing user-space to crash it.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2022-11-25 17:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-25 15:32 [PATCH] gpiolib: cdev: fix NULL-pointer dereferences Bartosz Golaszewski
2022-11-25 16:24 ` Kent Gibson
2022-11-25 16:48 ` Bartosz Golaszewski
2022-11-25 17:56 ` Andy Shevchenko [this message]
2022-11-25 18:02 ` Andy Shevchenko
2022-11-25 21:03 ` Bartosz Golaszewski
2022-11-25 21:33 ` Andy Shevchenko
2022-11-26 0:39 ` Kent Gibson
2022-11-26 4:02 ` kernel test robot
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