From: Ralph Campbell <rcampbell@nvidia.com>
To: <linux-mm@kvack.org>
Cc: linux-kernel@vger.kernel.org,
"Ralph Campbell" <rcampbell@nvidia.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"Mike Kravetz" <mike.kravetz@oracle.com>,
"Christoph Hellwig" <hch@lst.de>,
"Jason Gunthorpe" <jgg@mellanox.com>,
stable@vger.kernel.org,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: [PATCH 3/3] mm/hmm: Fix bad subpage pointer in try_to_unmap_one
Date: Tue, 16 Jul 2019 17:14:46 -0700 [thread overview]
Message-ID: <20190717001446.12351-4-rcampbell@nvidia.com> (raw)
In-Reply-To: <20190717001446.12351-1-rcampbell@nvidia.com>
When migrating an anonymous private page to a ZONE_DEVICE private page,
the source page->mapping and page->index fields are copied to the
destination ZONE_DEVICE struct page and the page_mapcount() is increased.
This is so rmap_walk() can be used to unmap and migrate the page back to
system memory. However, try_to_unmap_one() computes the subpage pointer
from a swap pte which computes an invalid page pointer and a kernel panic
results such as:
BUG: unable to handle page fault for address: ffffea1fffffffc8
Currently, only single pages can be migrated to device private memory so
no subpage computation is needed and it can be set to "page".
Fixes: a5430dda8a3a1c ("mm/migrate: support un-addressable ZONE_DEVICE page in migration")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/rmap.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/rmap.c b/mm/rmap.c
index e5dfe2ae6b0d..ec1af8b60423 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1476,6 +1476,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
* No need to invalidate here it will synchronize on
* against the special swap migration pte.
*/
+ subpage = page;
goto discard;
}
--
2.20.1
next prev parent reply other threads:[~2019-07-17 0:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 0:14 [PATCH 0/3] mm/hmm: fixes for device private page migration Ralph Campbell
2019-07-17 0:14 ` [PATCH 1/3] mm: document zone device struct page reserved fields Ralph Campbell
2019-07-17 1:20 ` John Hubbard
2019-07-17 4:22 ` Christoph Hellwig
2019-07-17 4:31 ` John Hubbard
2019-07-17 4:38 ` Christoph Hellwig
2019-07-17 17:50 ` Ralph Campbell
2019-07-17 0:14 ` [PATCH 2/3] mm/hmm: fix ZONE_DEVICE anon page mapping reuse Ralph Campbell
2019-07-17 1:40 ` John Hubbard
2019-07-17 0:14 ` Ralph Campbell [this message]
2019-07-17 1:51 ` [PATCH 3/3] mm/hmm: Fix bad subpage pointer in try_to_unmap_one John Hubbard
2019-07-19 19:06 [PATCH 0/3] mm/hmm: fixes for device private page migration Ralph Campbell
2019-07-19 19:06 ` [PATCH 3/3] mm/hmm: Fix bad subpage pointer in try_to_unmap_one Ralph Campbell
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190717001446.12351-4-rcampbell@nvidia.com \
--to=rcampbell@nvidia.com \
--cc=akpm@linux-foundation.org \
--cc=hch@lst.de \
--cc=jgg@mellanox.com \
--cc=jglisse@redhat.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mike.kravetz@oracle.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).