From: Miklos Szeredi <miklos@szeredi.hu>
To: Christoph Hellwig <hch@infradead.org>
Cc: syzbot <syzbot+5b1df0420c523b45a953@syzkaller.appspotmail.com>,
bcrl <bcrl@kvack.org>, linux-aio <linux-aio@kvack.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: possible deadlock in aio_poll
Date: Tue, 11 Sep 2018 09:20:40 +0200 [thread overview]
Message-ID: <CAJfpegtS8QMfhNMFV3i6GycqmXsLNYXvKjRm3wG79PFuF1VvuA@mail.gmail.com> (raw)
In-Reply-To: <20180911063335.GA3315@infradead.org>
On Tue, Sep 11, 2018 at 8:33 AM, Christoph Hellwig <hch@infradead.org> wrote:
> On Mon, Sep 10, 2018 at 08:14:20PM +0200, Miklos Szeredi wrote:
>> Why do pollable waitqueues need to disable interrupts generally?
>
> Any waitqueue needs to disable interrupts for consistency. We
> always use spin_lock_irqsave in __wake_up_common_lock() for example.
There are the _locked (non _irq) variants that do not.
And poll/select/etc don't impose non-interuptibility on wakeups
either. So it looks like it's just aio that has weird spin lock
dependencies that forces this requirement on a waitq used in ->poll().
Thanks,
Miklos
next prev parent reply other threads:[~2018-09-11 12:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-10 7:41 possible deadlock in aio_poll syzbot
2018-09-10 16:53 ` Christoph Hellwig
2018-09-10 18:14 ` Miklos Szeredi
2018-09-11 6:33 ` Christoph Hellwig
2018-09-11 7:20 ` Miklos Szeredi [this message]
2018-10-17 23:55 ` Andrea Arcangeli
2018-10-27 6:16 ` syzbot
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