From: Peter Xu <peterx@redhat.com>
To: Alistair Popple <alistair@popple.id.au>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Andrew Morton" <akpm@linux-foundation.org>,
"Jérôme Glisse" <jglisse@redhat.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Ralph Campbell" <rcampbell@nvidia.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2 2/2] mm/rmap: Fixup copying of soft dirty and uffd ptes
Date: Tue, 25 Aug 2020 10:42:03 -0400 [thread overview]
Message-ID: <20200825144203.GA8235@xz-x1> (raw)
In-Reply-To: <20200825064232.10023-2-alistair@popple.id.au>
On Tue, Aug 25, 2020 at 04:42:32PM +1000, Alistair Popple wrote:
> During memory migration a pte is temporarily replaced with a migration
> swap pte. Some pte bits from the existing mapping such as the soft-dirty
> and uffd write-protect bits are preserved by copying these to the
> temporary migration swap pte.
>
> However these bits are not stored at the same location for swap and
> non-swap ptes. Therefore testing these bits requires using the
> appropriate helper function for the given pte type.
>
> Unfortunately several code locations were found where the wrong helper
> function is being used to test soft_dirty and uffd_wp bits which leads
> to them getting incorrectly set or cleared during page-migration.
>
> Fix these by using the correct tests based on pte type.
>
> Fixes: a5430dda8a3a ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
> Fixes: 8c3328f1f36a ("mm/migrate: migrate_vma() unmap page from vma while collecting pages")
> Fixes: f45ec5ff16a7 ("userfaultfd: wp: support swap and page migration")
> Signed-off-by: Alistair Popple <alistair@popple.id.au>
> Cc: stable@vger.kernel.org
Reviewed-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
prev parent reply other threads:[~2020-08-25 14:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-25 6:42 [PATCH v2 1/2] mm/migrate: Fixup setting UFFD_WP flag Alistair Popple
2020-08-25 6:42 ` [PATCH v2 2/2] mm/rmap: Fixup copying of soft dirty and uffd ptes Alistair Popple
2020-08-25 14:42 ` Peter Xu [this message]
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