Messages in this thread | | | Subject | Re: [PATCH] vhost/net: length miscalculation | From | Alex Williamson <> | Date | Wed, 07 Jan 2015 08:09:04 -0700 |
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On Wed, 2015-01-07 at 10:55 +0200, Michael S. Tsirkin wrote: > commit 8b38694a2dc8b18374310df50174f1e4376d6824 > vhost/net: virtio 1.0 byte swap > had this chunk: > - heads[headcount - 1].len += datalen; > + heads[headcount - 1].len = cpu_to_vhost32(vq, len - datalen); > > This adds datalen with the wrong sign, causing guest panics. > > Fixes: 8b38694a2dc8b18374310df50174f1e4376d6824 > Reported-by: Alex Williamson <alex.williamson@redhat.com> > Suggested-by: Greg Kurz <gkurz@linux.vnet.ibm.com> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > --- > > Alex, could you please confirm this fixes the crash for you?
Confirmed, this works. Thanks,
Alex
> drivers/vhost/net.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c > index 14419a8..d415d69 100644 > --- a/drivers/vhost/net.c > +++ b/drivers/vhost/net.c > @@ -538,7 +538,7 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, > ++headcount; > seg += in; > } > - heads[headcount - 1].len = cpu_to_vhost32(vq, len - datalen); > + heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); > *iovcount = seg; > if (unlikely(log)) > *log_num = nlogs;
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