Sasha Levin
2020-Feb-14 16:17 UTC
[PATCH AUTOSEL 4.14 185/186] virtio_balloon: prevent pfn array overflow
From: "Michael S. Tsirkin" <mst at 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 at redhat.com>
Reviewed-by: David Hildenbrand <david at redhat.com>
Signed-off-by: Sasha Levin <sashal at 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 499531608fa26..71970773aad13 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -132,6 +132,8 @@ 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