Messages in this thread | | | Date | Fri, 1 Jan 2016 10:26:32 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH 1/2] virtio_balloon: fix race by fill and leak |
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On Mon, Dec 28, 2015 at 08:35:12AM +0900, Minchan Kim wrote: > During my compaction-related stuff, I encountered a bug > with ballooning. > > With repeated inflating and deflating cycle, guest memory( > ie, cat /proc/meminfo | grep MemTotal) is decreased and > couldn't be recovered. > > The reason is balloon_lock doesn't cover release_pages_balloon > so struct virtio_balloon fields could be overwritten by race > of fill_balloon(e,g, vb->*pfns could be critical). > > This patch fixes it in my test. > > Cc: <stable@vger.kernel.org> > Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> --- > drivers/virtio/virtio_balloon.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c > index 7efc32945810..7d3e5d0e9aa4 100644 > --- a/drivers/virtio/virtio_balloon.c > +++ b/drivers/virtio/virtio_balloon.c > @@ -209,8 +209,8 @@ static unsigned leak_balloon(struct virtio_balloon *vb, size_t num) > */ > if (vb->num_pfns != 0) > tell_host(vb, vb->deflate_vq); > - mutex_unlock(&vb->balloon_lock); > release_pages_balloon(vb); > + mutex_unlock(&vb->balloon_lock); > return num_freed_pages; > } > > -- > 1.9.1
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