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Subject: Re: [PATCH v3 0/1] mm: introduce put_user_page*(), placeholder
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From:   William Kucharski <william.kucharski@oracle.com>
In-Reply-To: <20190314133038.GJ16658@quack2.suse.cz>
Date:   Thu, 14 Mar 2019 14:25:35 -0600
Cc:     Jason Gunthorpe <jgg@ziepe.ca>, Christopher Lameter <cl@linux.com>,
        Jerome Glisse <jglisse@redhat.com>, john.hubbard@gmail.com,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christian Benvenuti <benve@cisco.com>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Chinner <david@fromorbit.com>,
        Dennis Dalessandro <dennis.dalessandro@intel.com>,
        Doug Ledford <dledford@redhat.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Michal Hocko <mhocko@kernel.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Mike Marciniszyn <mike.marciniszyn@intel.com>,
        Ralph Campbell <rcampbell@nvidia.com>,
        Tom Talpey <tom@talpey.com>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org, John Hubbard <jhubbard@nvidia.com>
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To:     Jan Kara <jack@suse.cz>
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> On Mar 14, 2019, at 7:30 AM, Jan Kara <jack@suse.cz> wrote:
> 
> Well I have some crash reports couple years old and they are not from QA
> departments. So I'm pretty confident there are real users that use this in
> production... and just reboot their machine in case it crashes.

Do you know what the use case in those crashes actually was?

I'm curious to know they were actually cases of say DMA from a video
capture card or if the uses posited to date are simply theoretical.

It's always good to know who might be doing this and why if for no other
reason than as something to keep in mind when designing future interfaces.