[PATCH v2] net: mediatek: add null pointer check for hardware offloading

[Sebastian Roland Wolf]

From: Sebastian Roland Wolf <srw at root533.premium-rootserver.net>

Add a null pointer check to prevent kernel crashes when hardware
offloading is active on MediaTek devices.

In some edge cases, the ethernet pointer or its associated netdev
element can be NULL. Checking these pointers before access is
mandatory to avoid segmentation faults and kernel oops.

This improves the robustness of the validation check for mtk_eth
ingress devices introduced in commit 73cfd947dbdb ("net: mediatek:
add support for ingress traffic offloading").

Fixes: 73cfd947dbdb ("net: mediatek: add support for ingress traffic offloading")
net: mediatek: Add null pointer check to prevent crashes with active hardware offloading.

Signed-off-by: Sebastian Roland Wolf <Sebastian.Wolf at pace-systems.de>
---
 drivers/net/ethernet/mediatek/mtk_ppe_offload.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_ppe_offload.c b/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
index e9bd32741983..72bc4a42eac1 100644
--- a/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
+++ b/drivers/net/ethernet/mediatek/mtk_ppe_offload.c
@@ -270,7 +270,8 @@ 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 && eth->netdev[0] &&
+			    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))
-- 
2.51.0