int b43_dma_init(struct b43_wldev *dev)
{
	struct b43_dma *dma = &dev->dma;
	int err;
	u64 dmamask;
	enum b43_dmatype type;

	dmamask = supported_dma_mask(dev);
	type = dma_mask_to_engine_type(dmamask);
	err = b43_dma_set_mask(dev, dmamask);
	if (err)
		return err;

	err = -ENOMEM;
	/* setup TX DMA channels. */
	dma->tx_ring_AC_BK = b43_setup_dmaring(dev, 0, 1, type);
	if (!dma->tx_ring_AC_BK)
		goto out;

	dma->tx_ring_AC_BE = b43_setup_dmaring(dev, 1, 1, type);
	if (!dma->tx_ring_AC_BE)
		goto err_destroy_bk;

	dma->tx_ring_AC_VI = b43_setup_dmaring(dev, 2, 1, type);
	if (!dma->tx_ring_AC_VI)
		goto err_destroy_be;

	dma->tx_ring_AC_VO = b43_setup_dmaring(dev, 3, 1, type);
	if (!dma->tx_ring_AC_VO)
		goto err_destroy_vi;

	dma->tx_ring_mcast = b43_setup_dmaring(dev, 4, 1, type);
	if (!dma->tx_ring_mcast)
		goto err_destroy_vo;

	/* setup RX DMA channel. */
	dma->rx_ring = b43_setup_dmaring(dev, 0, 0, type);
	if (!dma->rx_ring)
		goto err_destroy_mcast;

	/* No support for the TX status DMA ring. */
	B43_WARN_ON(dev->dev->id.revision < 5);

	b43dbg(dev->wl, "%u-bit DMA initialized\n",
	       (unsigned int)type);
	err = 0;
out:
	return err;

err_destroy_mcast:
	destroy_ring(dma, tx_ring_mcast);
err_destroy_vo:
	destroy_ring(dma, tx_ring_AC_VO);
err_destroy_vi:
	destroy_ring(dma, tx_ring_AC_VI);
err_destroy_be:
	destroy_ring(dma, tx_ring_AC_BE);
err_destroy_bk:
	destroy_ring(dma, tx_ring_AC_BK);
	return err;
}

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.