On Fri, Feb 17, 2023 at 11:42 AM Laurent Vivier <lviv...@redhat.com> wrote: > > The problem has been reported by gcc with CFLAGS=-O3: > > .../hw/virtio/vhost-shadow-virtqueue.c: In function ‘vhost_svq_poll’: > .../hw/virtio/vhost-shadow-virtqueue.c:538:12: > error: ‘len’ may be used uninitialized [-Werror=maybe-uninitialized] > 538 | return len; > | ^~~ > > vhost_svq_get_buf() returns NULL if SVQ is empty but doesn't set len to 0, > and vhost_svq_poll() returns len without checking the return of > vhost_svq_get_buf(). So if the SVQ is empty vhost_svq_poll() can return > an random value. >
s/an random/a random/. I think this solves the same as https://www.mail-archive.com/qemu-devel@nongnu.org/msg939383.html ? Thanks! > Signed-off-by: Laurent Vivier <lviv...@redhat.com> > --- > hw/virtio/vhost-shadow-virtqueue.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/virtio/vhost-shadow-virtqueue.c > b/hw/virtio/vhost-shadow-virtqueue.c > index 430729635815..31cf642db267 100644 > --- a/hw/virtio/vhost-shadow-virtqueue.c > +++ b/hw/virtio/vhost-shadow-virtqueue.c > @@ -420,6 +420,7 @@ static VirtQueueElement > *vhost_svq_get_buf(VhostShadowVirtqueue *svq, > vring_used_elem_t used_elem; > uint16_t last_used, last_used_chain, num; > > + *len = 0; > if (!vhost_svq_more_used(svq)) { > return NULL; > } > -- > 2.39.1 >
