void CommandBufferProxyImpl::Flush(int32_t put_offset) {
  CheckLock();
  base::AutoLock lock(last_state_lock_);
  if (last_state_.error != gpu::error::kNoError)
    return;

  TRACE_EVENT1("gpu", "CommandBufferProxyImpl::Flush", "put_offset",
               put_offset);

  OrderingBarrierHelper(put_offset);

  if (!disconnected_)
    channel_->EnsureFlush(last_flush_id_);
}

The product writes data past the end, or before the beginning, of the intended buffer.