| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.4 457/459] virtio_balloon: prevent pfn array overflow | Date | Fri, 14 Feb 2020 11:01:47 -0500 |
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From: "Michael S. Tsirkin" <mst@redhat.com>
[ Upstream commit 6e9826e77249355c09db6ba41cd3f84e89f4b614 ]
Make sure, at build time, that pfn array is big enough to hold a single page. It happens to be true since the PAGE_SHIFT value at the moment is 20, which is 1M - exactly 256 4K balloon pages.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index c962d9b370c69..d2c4eb9efd70b 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -157,6 +157,8 @@ static void set_page_pfns(struct virtio_balloon *vb, { unsigned int i; + BUILD_BUG_ON(VIRTIO_BALLOON_PAGES_PER_PAGE > VIRTIO_BALLOON_ARRAY_PFNS_MAX); + /* * Set balloon pfns pointing at this page. * Note that the first pfn points at start of the page. -- 2.20.1
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