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Date:   Sat, 12 Sep 2020 00:55:11 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Qian Cai <cai@lca.pw>
Cc:     torvalds@linux-foundation.org, vgoyal@redhat.com,
        miklos@szeredi.hu, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: slab-out-of-bounds in iov_iter_revert()
Message-ID: <20200911235511.GB3421308@ZenIV.linux.org.uk>
References: <20200911215903.GA16973@lca.pw>
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On Fri, Sep 11, 2020 at 05:59:04PM -0400, Qian Cai wrote:
> Super easy to reproduce on today's mainline by just fuzzing for a few minutes
> on virtiofs (if it ever matters). Any thoughts?

Usually happens when ->direct_IO() fucks up and reports the wrong amount
of data written/read.  We had several bugs like that in the past - see
e.g. 85128b2be673 (fix nfs O_DIRECT advancing iov_iter too much).

Had there been any recent O_DIRECT-related patches on the filesystems
involved?