From 6e9826e77249355c09db6ba41cd3f84e89f4b614 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Thu, 6 Feb 2020 02:40:58 -0500
Subject: [PATCH] virtio_balloon: prevent pfn array overflow
Git-commit: 6e9826e77249355c09db6ba41cd3f84e89f4b614
Patch-mainline: v5.6-rc1
References: git-fixes
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 8e400ece9273..2457c54b6185 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -158,6 +158,8 @@ 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.
--
2.16.4