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Date:   Tue, 9 Jul 2019 17:28:23 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Ralph Campbell <rcampbell@nvidia.com>
Cc:     <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
        =?ISO-8859-1?Q?J?= =?ISO-8859-1?Q?=E9r=F4me?= Glisse 
        <jglisse@redhat.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Mike Kravetz <mike.kravetz@oracle.com>
Subject: Re: [PATCH] mm/hmm: Fix bad subpage pointer in try_to_unmap_one
Message-Id: <20190709172823.9413bb2333363f7e33a471a0@linux-foundation.org>
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On Tue, 9 Jul 2019 15:35:56 -0700 Ralph Campbell <rcampbell@nvidia.com> wrote:

> When migrating a ZONE device private page from device memory to system
> memory, the subpage pointer is initialized from a swap pte which computes
> an invalid page pointer. A kernel panic results such as:
> 
> BUG: unable to handle page fault for address: ffffea1fffffffc8
> 
> Initialize subpage correctly before calling page_remove_rmap().

I think this is

Fixes:  a5430dda8a3a1c ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Cc: stable

yes?