On Wed, 5 Jun 2013 21:18:37 -0400 Luiz Capitulino <lcapitul...@redhat.com> wrote:
> The balloon_page_dequeue() function can return NULL. If it does for > the first page being freed, then leak_balloon() will create a > scatter list with len=0. Which in turn seems to generate an invalid > virtio request. > > I didn't get this in practice, I found it by code review. On the other > hand, such an invalid virtio request will cause errors in QEMU and > fill_balloon() also performs the same check implemented by this commit. > > Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com> > Acked-by: Rafael Aquini <aqu...@redhat.com> Andrew, can you pick this one? > --- > > o v2 > > - Improve changelog > > drivers/virtio/virtio_balloon.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index bd3ae32..71af7b5 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -191,7 +191,8 @@ static void leak_balloon(struct virtio_balloon *vb, > size_t num) > * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST); > * is true, we *have* to do it in this order > */ > - tell_host(vb, vb->deflate_vq); > + if (vb->num_pfns != 0) > + tell_host(vb, vb->deflate_vq); > mutex_unlock(&vb->balloon_lock); > release_pages_by_pfn(vb->pfns, vb->num_pfns); > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
