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Date:   Mon, 4 Feb 2019 18:49:00 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Bart Van Assche <bvanassche@acm.org>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
        syzbot <syzkaller@googlegroups.com>,
        Christoph Hellwig <hch@lst.de>, Avi Kivity <avi@scylladb.com>,
        Eric Dumazet <edumazet@google.com>, stable@vger.kernel.org
Subject: Re: [PATCH] aio: Fix locking in aio_poll()
Message-ID: <20190204174900.GA16229@lst.de>
References: <20190204174555.83603-1-bvanassche@acm.org>
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On Mon, Feb 04, 2019 at 09:45:55AM -0800, Bart Van Assche wrote:
> Since kioctx.ctx_lock may be acquired from IRQ context, all code that
> acquires that lock from thread context must disable interrupts. This
> patch fixes the following lockdep complaint:

But breaks the real life users of this interface :(

aio_poll_wake is assigned as the wake function to a waitqueue,
and the waitqueue interface requires that function to be called
with irqs disabled.  It looks like the fuse code is breaking that
contract, so we need to fix that instead of disable irqs.