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Date:   Sun, 14 May 2023 22:14:46 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Lorenzo Stoakes <lstoakes@gmail.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
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        Mark Rutland <mark.rutland@arm.com>,
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Subject: Re: [PATCH v9 0/3] mm/gup: disallow GUP writing to file-backed
 mappings by default
Message-ID: <ZGG/xkIUYK2QMPSv@infradead.org>
References: <cover.1683235180.git.lstoakes@gmail.com>
 <0eb31f6f-a122-4a5b-a959-03ed4dee1f3c@lucifer.local>
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On Sun, May 14, 2023 at 08:20:04PM +0100, Lorenzo Stoakes wrote:
> As discussed at LSF/MM, on the flight over I wrote a little repro [0] which
> reliably triggers the ext4 warning by recreating the scenario described
> above, using a small userland program and kernel module.
> 
> This code is not perfect (plane code :) but does seem to do the job
> adequately, also obviously this should only be run in a VM environment
> where data loss is acceptable (in my case a small qemu instance).

It would be really awesome if you could wire it up with and submit it
to xfstests.