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Date:   Thu, 23 May 2019 23:40:51 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Jerome Glisse <jglisse@redhat.com>, linux-kernel@vger.kernel.org,
        linux-rdma@vger.kernel.org, Leon Romanovsky <leonro@mellanox.com>,
        Doug Ledford <dledford@redhat.com>,
        Artemy Kovalyov <artemyko@mellanox.com>,
        Moni Shoua <monis@mellanox.com>,
        Mike Marciniszyn <mike.marciniszyn@intel.com>,
        Kaike Wan <kaike.wan@intel.com>,
        Dennis Dalessandro <dennis.dalessandro@intel.com>,
        linux-mm@kvack.org, akpm@linux-foundation.org
Subject: Re: [PATCH v4 0/1] Use HMM for ODP v4
Message-ID: <20190524064051.GA28855@infradead.org>
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On Thu, May 23, 2019 at 04:10:38PM -0300, Jason Gunthorpe wrote:
> 
> On Thu, May 23, 2019 at 02:24:58PM -0400, Jerome Glisse wrote:
> > I can not take mmap_sem in range_register, the READ_ONCE is fine and
> > they are no race as we do take a reference on the hmm struct thus
> 
> Of course there are use after free races with a READ_ONCE scheme, I
> shouldn't have to explain this.
> 
> If you cannot take the read mmap sem (why not?), then please use my
> version and push the update to the driver through -mm..

I think it would really help if we queue up these changes in a git tree
that can be pulled into the driver trees.  Given that you've been
doing so much work to actually make it usable I'd nominate rdma for the
"lead" tree.