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| author | Luiz Capitulino <lcapitulino@redhat.com> | 2013-07-02 15:35:13 +0930 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2013-07-02 15:42:03 +0930 |
| commit | 8c6bab4f3874d31804a00782c48a8f244a0d3cc0 (patch) | |
| tree | 2d030280d60b94b6b8b5fbd3a49f79ff7ea710f6 /drivers/virtio/virtio_balloon.c | |
| parent | f11335db5e3901f6afc2eafa03a3b970562538b2 (diff) | |
| download | blackbird-obmc-linux-8c6bab4f3874d31804a00782c48a8f244a0d3cc0.tar.gz blackbird-obmc-linux-8c6bab4f3874d31804a00782c48a8f244a0d3cc0.zip | |
virtio_balloon: leak_balloon(): only tell host if we got pages deflated
balloon_page_dequeue() 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.
This bug was introduced in e2250429.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # 3.9
Diffstat (limited to 'drivers/virtio/virtio_balloon.c')
| -rw-r--r-- | drivers/virtio/virtio_balloon.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index bd3ae324a1a2..71af7b5abe01 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); } |
