From: Luiz Capitulino <lcapitulino@redhat.com>
Date: Tue, 2 Jul 2013 06:05:13 +0000 (+0930)
Subject: virtio_balloon: leak_balloon(): only tell host if we got pages deflated
X-Git-Tag: v3.11-rc1~45^2~8
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8c6bab4f3874d31804a00782c48a8f244a0d3cc0;p=pandora-kernel.git

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
---

Reading git-diff-tree failed