    dma_addr_t map_descbuffer(struct b43_dmaring *ring,
			      unsigned char *buf, size_t len, int tx)
{
	dma_addr_t dmaaddr;

	if (tx) {
		dmaaddr = dma_map_single(ring->dev->dev->dma_dev,
					 buf, len, DMA_TO_DEVICE);
	} else {
		dmaaddr = dma_map_single(ring->dev->dev->dma_dev,
					 buf, len, DMA_FROM_DEVICE);
	}

	return dmaaddr;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.