From 36a05d2820077bb3955acb8111e1041d39148037 Mon Sep 17 00:00:00 2001 From: Siddharth Vadapalli Date: Fri, 7 Aug 2026 16:47:37 +0530 Subject: [PATCH] net: ethernet: ti: am65-cpsw-nuss: Fix port_id extraction from SRC TAG On the packet reception path, the ID of the MAC Port on which the packet was received, is embedded in the RX DMA Descriptor's metadata. The ID is extracted using the helper function cppi5_desc_get_tags_ids() which fills in the 16-bit Source Tag into the 'port_id' variable. However, it is only the lower 8-bits of the 16-bit Source Tag that represent the MAC Port ID, while the upper 8-bits are Hardware-Reserved and carry an arbitrary value. With the existing logic, sporadic kernel crash is observed due to the subsequent driver code accessing out-of-bound memory because of an invalid port_id. Hence, fix the port_id extraction logic to use only the lower 8-bits of the Source Tag as the MAC Port ID. Fixes: 93a76530316a ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver") Signed-off-by: Siddharth Vadapalli Reviewed-by: Chintan Vankar Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260807111738.2055900-1-s-vadapalli@ti.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/ti/am65-cpsw-nuss.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c index 434a31080855..6330540979d7 100644 --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c @@ -1310,6 +1310,8 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_rx_flow *flow, k3_udma_glue_rx_cppi5_to_dma_addr(rx_chn->rx_chn, &buf_dma); pkt_len = cppi5_hdesc_get_pktlen(desc_rx); cppi5_desc_get_tags_ids(&desc_rx->hdr, &port_id, NULL); + /* Port ID is contained in the lower 8-bits of the 16-bit Source Tag */ + port_id &= 0xFF; dev_dbg(dev, "%s rx port_id:%d\n", __func__, port_id); port = am65_common_get_port(common, port_id); ndev = port->ndev; -- 2.30.2