2.6.38-stable review patch. If anyone has any objections, please let us know.
------------------ From: Amit Shah <[email protected]> commit b3258ff1d6086bd2b9eeb556844a868ad7d49bc8 upstream. When detaching a buffer from a vq, the avail.idx value should be decremented as well. This was noticed by hot-unplugging a virtio console port and then plugging in a new one on the same number (re-using the vqs which were just 'disowned'). qemu reported 'Guest moved used index from 0 to 256' when any IO was attempted on the new port. Reported-by: juzhang <[email protected]> Signed-off-by: Amit Shah <[email protected]> Signed-off-by: Rusty Russell <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/virtio/virtio_ring.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -371,6 +371,7 @@ void *virtqueue_detach_unused_buf(struct /* detach_buf clears data, so grab it now. */ buf = vq->data[i]; detach_buf(vq, i); + vq->vring.avail->idx--; END_USE(vq); return buf; } _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
