tree 2d030280d60b94b6b8b5fbd3a49f79ff7ea710f6
parent f11335db5e3901f6afc2eafa03a3b970562538b2
author Luiz Capitulino <lcapitulino@redhat.com> 1372745113 +0930
committer Rusty Russell <rusty@rustcorp.com.au> 1372745523 +0930

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