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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 6 Dec 2019 20:01:29 -0800
Message-ID: <CAHk-=whnf=avRa4JVoiEB+75mSpnAKuoQSFaxOJWHfqX3mqUqg@mail.gmail.com>
Subject: Re: [PATCH 0/2] pipe: Fixes [ver #2]
To:     David Sterba <dsterba@suse.cz>,
        David Howells <dhowells@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Eric Biggers <ebiggers@kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, Dec 6, 2019 at 7:50 PM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> I assume it's the added "do_wakeup = 0" (not the spinlock) that ends
> up having some subtle issue.

Ahh, and then later that is removed, but when it is removed it also
remote the wakeup before the pipe_wait(). So whatever issue that
commit introduces ends up remaining.

I wonder if the extra wakeups ended up hiding some other bug. We do
extra wakeups on the write side too, with a "FIXME! Is this really
true?" comment..

              Linus