Re: [PATCH v2] floppy: refactor open() flags handling (was Re: mm: uninterruptable tasks hanged on mmap_sem)

From	Dmitry Vyukov <dvyukov@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2] floppy: refactor open() flags handling (was Re: mm: uninterruptable tasks hanged on mmap_sem)
Date	2016-02-05 15:30 +0100
Message-ID	<qYPyx-1p9-3@gated-at.bofh.it> (permalink)
References	<qXQdk-cA-9@gated-at.bofh.it> <qYzDr-7yk-5@gated-at.bofh.it> <qYOVR-SY-29@gated-at.bofh.it> <qYP5y-Xo-43@gated-at.bofh.it>
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On Fri, Feb 5, 2016 at 2:51 PM, Jiri Kosina <jikos@kernel.org> wrote:
> On Fri, 5 Feb 2016, Dmitry Vyukov wrote:
>
>> > could you please feed the patch below (on top of the previous floppy fix)
>> > to your syzkaller machinery and test whether you are still able to
>> > reproduce the problem? It passess my local testing here.
>>
>> Now that open exits early with EWOULDBLOCK, I guess the reproduced is
>> not doing anything particularly interesting.
>
> Yeah. But as I explained in the changelog, I think it's a valid thing to
> do (opinions welcome).
>
> I don't think having a huge discussion about what nonblocking really means
> for floppy and then try to refactor the whole driver to support that would
> make sense.

I don't have any objections. And I agree that it does not make sense
to spend any considerable time on optimizing this driver.


> Alternatively we can take more conservative aproach, accept the
> nonblocking flag, but do the regular business of the driver.
>
> Actually, let's try that, to make sure that we don't introduce userspace
> breakage.
>
> Could you please retest with the patch below?

Reapplied.
Agree that it's better to not bail out on O_NONBLOCK.

Thread

mm: uninterruptable tasks hanged on mmap_sem Dmitry Vyukov <dvyukov@google.com> - 2016-02-02 22:00 +0100
  Re: mm: uninterruptable tasks hanged on mmap_sem Jiri Kosina <jikos@kernel.org> - 2016-02-02 22:10 +0100
    Re: mm: uninterruptable tasks hanged on mmap_sem Dmitry Vyukov <dvyukov@google.com> - 2016-02-02 22:20 +0100
      Re: mm: uninterruptable tasks hanged on mmap_sem Jiri Kosina <jikos@kernel.org> - 2016-02-02 22:30 +0100
        Re: mm: uninterruptable tasks hanged on mmap_sem Dmitry Vyukov <dvyukov@google.com> - 2016-02-02 22:40 +0100
      Re: mm: uninterruptable tasks hanged on mmap_sem Dmitry Vyukov <dvyukov@google.com> - 2016-02-02 22:30 +0100
  Re: mm: uninterruptable tasks hanged on mmap_sem Dmitry Vyukov <dvyukov@google.com> - 2016-02-03 14:20 +0100
  Re: mm: uninterruptable tasks hanged on mmap_sem Jiri Kosina <jikos@kernel.org> - 2016-02-03 14:20 +0100
  Re: mm: uninterruptable tasks hanged on mmap_sem Jiri Kosina <jikos@kernel.org> - 2016-02-04 00:40 +0100
  [PATCH] floppy: refactor open() flags handling (was Re: mm:  uninterruptable tasks hanged on mmap_sem) Jiri Kosina <jikos@kernel.org> - 2016-02-04 22:30 +0100
    Re: [PATCH] floppy: refactor open() flags handling (was Re: mm:  uninterruptable tasks hanged on mmap_sem) Dmitry Vyukov <dvyukov@google.com> - 2016-02-05 14:50 +0100
      [PATCH v2] floppy: refactor open() flags handling (was Re: mm:  uninterruptable tasks hanged on mmap_sem) Jiri Kosina <jikos@kernel.org> - 2016-02-05 15:00 +0100
        Re: [PATCH v2] floppy: refactor open() flags handling (was Re: mm:  uninterruptable tasks hanged on mmap_sem) Dmitry Vyukov <dvyukov@google.com> - 2016-02-05 15:30 +0100
          Re: [PATCH v2] floppy: refactor open() flags handling (was Re: mm:  uninterruptable tasks hanged on mmap_sem) Jiri Kosina <jikos@kernel.org> - 2016-02-05 17:50 +0100
            Re: [PATCH v2] floppy: refactor open() flags handling (was Re: mm:  uninterruptable tasks hanged on mmap_sem) Dmitry Vyukov <dvyukov@google.com> - 2016-02-05 22:20 +0100

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