Re: [PATCH net-next] net: ethernet: mtk_eth_soc: ppe: prevent ppe update for non-mtk devices
From: Sven Eckelmann <sven@narfation.org>
Date: 2026-03-23 10:35:59
Also in:
linux-arm-kernel, linux-mediatek, lkml
On Sunday, 23 June 2024 19:51:09 CET Elad Yifee wrote:
quoted hunk ↗ jump to hunk
Introduce an additional validation to ensure that the PPE index is modified exclusively for mtk_eth ingress devices. This primarily addresses the issue related to WED operation with multiple PPEs. Fixes: dee4dd10c79a ("net: ethernet: mtk_eth_soc: ppe: add support for multiple PPEs") Signed-off-by: Elad Yifee <redacted> --- drivers/net/ethernet/mediatek/mtk_ppe_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/drivers/net/ethernet/mediatek/mtk_ppe_offload.c b/drivers/net/ethernet/mediatek/mtk_ppe_offload.c index f80af73d0a1b..f20bb390df3a 100644 --- a/drivers/net/ethernet/mediatek/mtk_ppe_offload.c +++ b/drivers/net/ethernet/mediatek/mtk_ppe_offload.c@@ -266,7 +266,7 @@ mtk_flow_offload_replace(struct mtk_eth *eth, struct flow_cls_offload *f, flow_rule_match_meta(rule, &match); if (mtk_is_netsys_v2_or_greater(eth)) { idev = __dev_get_by_index(&init_net, match.key->ingress_ifindex); - if (idev) { + if (idev && idev->netdev_ops == eth->netdev[0]->netdev_ops) { struct mtk_mac *mac = netdev_priv(idev); if (WARN_ON(mac->ppe_idx >= eth->soc->ppe_num))
This will immediately cause a NULL-deref when gmac0 is disabled but gmac1 (or gmac2) is enabled - and you try to offload a flow. You have the problem that `eth->netdev[0]` is NULL and then you try to deref it to get to its netdev_ops. Btw. can you describe what netdev[0] makes it so special that you need to check for it and not netdev[1] or netdev[2]? With something like:
diff --git i/drivers/net/ethernet/mediatek/mtk_ppe_offload.c w/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
index cb30108f2bf6..5f88ad7eb27a 100644
--- i/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
+++ w/drivers/net/ethernet/mediatek/mtk_ppe_offload.c@@ -244,6 +244,21 @@ mtk_flow_set_output_device(struct mtk_eth *eth, struct mtk_foe_entry *foe, return 0; } +static bool mtk_is_valid_mtk_netdev(const struct mtk_eth *eth, const struct net_device *idev) +{ + size_t i; + + for (i = 0; i < ARRAY_SIZE(eth->netdev); i++) { + if (!eth->netdev[i]) + continue; + + if (idev->netdev_ops == eth->netdev[i]->netdev_ops) + return true; + } + + return false; +} + static int mtk_flow_offload_replace(struct mtk_eth *eth, struct flow_cls_offload *f, int ppe_index)
@@ -270,7 +285,7 @@ mtk_flow_offload_replace(struct mtk_eth *eth, struct flow_cls_offload *f, flow_rule_match_meta(rule, &match); if (mtk_is_netsys_v2_or_greater(eth)) { idev = __dev_get_by_index(&init_net, match.key->ingress_ifindex); - if (idev && idev->netdev_ops == eth->netdev[0]->netdev_ops) { + if (idev && mtk_is_valid_mtk_netdev(eth, idev)) { struct mtk_mac *mac = netdev_priv(idev); if (WARN_ON(mac->ppe_idx >= eth->soc->ppe_num))
Regards, Sven
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