[PATCH net v2] net: ti: icssg-prueth: fix XDP_TX from the AF_XDP zero-copy RX path
From: David Carlier <hidden>
Date: 2026-06-23 11:22:31
Also in:
bpf, linux-arm-kernel, lkml, stable
Subsystem:
networking drivers, the rest, ti icssg ethernet driver (icssg) · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
On XDP_TX from the zero-copy RX path, emac_run_xdp() converts the xsk
buffer via xdp_convert_zc_to_xdp_frame(), which clones the data into a
fresh MEM_TYPE_PAGE_ORDER0 page that is not DMA mapped. Transmitting it
as PRUETH_TX_BUFF_TYPE_XDP_TX derives the DMA address with
page_pool_get_dma_addr(), reading an uninitialized page->dma_addr, so
the device DMAs from a bogus address (corrupt TX, or an IOMMU fault).
Pick the TX buffer type from the frame's memory type: keep
PRUETH_TX_BUFF_TYPE_XDP_TX for page_pool frames and use
PRUETH_TX_BUFF_TYPE_XDP_NDO for the cloned zero-copy frame, which is then
DMA mapped through the NDO path and unmapped on completion.
While at it, fix the page_pool XDP_TX completion path. A
PRUETH_TX_BUFF_TYPE_XDP_TX frame carries a page_pool-owned DMA mapping
(established against rx_chn->dma_dev), yet prueth_xmit_free()
unconditionally calls dma_unmap_single() on it with tx_chn->dma_dev,
tearing down a mapping the driver does not own; xdp_return_frame()
already recycles the page back to the pool. Tag such frames with a
dedicated PRUETH_SWDATA_XDPF_TX type so the completion path skips the
unmap, the same way PRUETH_SWDATA_XSK buffers are handled.
Fixes: 7a64bb388df3 ("net: ti: icssg-prueth: Add AF_XDP zero copy for RX")
Fixes: 62aa3246f462 ("net: ti: icssg-prueth: Add XDP support")
Cc: stable@vger.kernel.org
Signed-off-by: David Carlier <redacted>
---
v2:
- fold in the page_pool XDP_TX completion-path unmap fix raised by
Meghana Malladi: tag page_pool TX frames with PRUETH_SWDATA_XDPF_TX
so prueth_xmit_free() skips dma_unmap_single() on a pool-owned
mapping; xdp_return_frame() already recycles the page.
- add Fixes: 62aa3246f462 for that path.
- no change to the original zero-copy fix.
v1: https://lore.kernel.org/netdev/20260620213756.87499-1-devnexen@gmail.com (local)
drivers/net/ethernet/ti/icssg/icssg_common.c | 20 +++++++++++++++++---
drivers/net/ethernet/ti/icssg/icssg_prueth.h | 1 +
2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/ti/icssg/icssg_common.c b/drivers/net/ethernet/ti/icssg/icssg_common.c
index 82ddef9c17d5..96c8bf5ef671 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_common.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_common.c@@ -185,7 +185,7 @@ void prueth_xmit_free(struct prueth_tx_chn *tx_chn, first_desc = desc; next_desc = first_desc; swdata = cppi5_hdesc_get_swdata(first_desc); - if (swdata->type == PRUETH_SWDATA_XSK) + if (swdata->type == PRUETH_SWDATA_XSK || swdata->type == PRUETH_SWDATA_XDPF_TX) goto free_pool; cppi5_hdesc_get_obuf(first_desc, &buf_dma, &buf_dma_len);
@@ -259,6 +259,7 @@ int emac_tx_complete_packets(struct prueth_emac *emac, int chn, napi_consume_skb(skb, budget); break; case PRUETH_SWDATA_XDPF: + case PRUETH_SWDATA_XDPF_TX: xdpf = swdata->data.xdpf; dev_sw_netstats_tx_add(ndev, 1, xdpf->len); total_bytes += xdpf->len;
@@ -769,7 +770,8 @@ u32 emac_xmit_xdp_frame(struct prueth_emac *emac, k3_udma_glue_tx_dma_to_cppi5_addr(tx_chn->tx_chn, &buf_dma); cppi5_hdesc_attach_buf(first_desc, buf_dma, xdpf->len, buf_dma, xdpf->len); swdata = cppi5_hdesc_get_swdata(first_desc); - swdata->type = PRUETH_SWDATA_XDPF; + swdata->type = buff_type == PRUETH_TX_BUFF_TYPE_XDP_TX ? + PRUETH_SWDATA_XDPF_TX : PRUETH_SWDATA_XDPF; swdata->data.xdpf = xdpf; /* Report BQL before sending the packet */
@@ -804,6 +806,7 @@ EXPORT_SYMBOL_GPL(emac_xmit_xdp_frame); */ static u32 emac_run_xdp(struct prueth_emac *emac, struct xdp_buff *xdp, u32 *len) { + enum prueth_tx_buff_type tx_buff_type; struct net_device *ndev = emac->ndev; struct netdev_queue *netif_txq; int cpu = smp_processor_id();
@@ -826,11 +829,21 @@ static u32 emac_run_xdp(struct prueth_emac *emac, struct xdp_buff *xdp, u32 *len goto drop; } + /* In AF_XDP zero-copy mode xdp_convert_buff_to_frame() + * clones the xsk buffer into a fresh MEM_TYPE_PAGE_ORDER0 + * page that is not DMA mapped. Such a frame must be mapped + * via the NDO path; only a page pool-backed frame already + * carries a usable page_pool DMA address. + */ + tx_buff_type = xdpf->mem_type == MEM_TYPE_PAGE_POOL ? + PRUETH_TX_BUFF_TYPE_XDP_TX : + PRUETH_TX_BUFF_TYPE_XDP_NDO; + q_idx = cpu % emac->tx_ch_num; netif_txq = netdev_get_tx_queue(ndev, q_idx); __netif_tx_lock(netif_txq, cpu); result = emac_xmit_xdp_frame(emac, xdpf, q_idx, - PRUETH_TX_BUFF_TYPE_XDP_TX); + tx_buff_type); __netif_tx_unlock(netif_txq); if (result == ICSSG_XDP_CONSUMED) { ndev->stats.tx_dropped++;
@@ -1395,6 +1408,7 @@ void prueth_tx_cleanup(void *data, dma_addr_t desc_dma) dev_kfree_skb_any(skb); break; case PRUETH_SWDATA_XDPF: + case PRUETH_SWDATA_XDPF_TX: xdpf = swdata->data.xdpf; xdp_return_frame(xdpf); break;
diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.h b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
index df93d15c5b78..00bb760d68a9 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_prueth.h
+++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.h@@ -153,6 +153,7 @@ enum prueth_swdata_type { PRUETH_SWDATA_CMD, PRUETH_SWDATA_XDPF, PRUETH_SWDATA_XSK, + PRUETH_SWDATA_XDPF_TX, }; enum prueth_tx_buff_type {
--
2.53.0