A computer implemented method, apparatus, and computer program product for a checkpoint process associated with a device driver in a workload partitioned environment. In response to initiation of a checkpoint process, a stream is frozen. The stream comprises a set of kernel modules driving a device. Freezing the stream prevents any module in the set of kernel modules from sending any messages, other than a checkpoint message, to another module in the set of kernel modules. The message block for each module in the set of kernel modules is updated with internal data to form a restart message. The internal data is data describing a state of the module in the set of kernel modules.