[PATCH net] net: ethernet: mtk_eth_soc: fix NULL pointer on hw reset

[Daniel Golle]

When a hardware reset is triggered on devices not initializing WED the
calls to mtk_wed_fe_reset and mtk_wed_fe_reset_complete dereference a
pointer on uninitialized stack memory.
Initialize the hw_list will 0s and break out of both functions in case
a hw_list entry is 0.

Fixes: 08a764a7c51b ("net: ethernet: mtk_wed: add reset/reset_complete callbacks")
Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
 drivers/net/ethernet/mediatek/mtk_wed.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/ethernet/mediatek/mtk_wed.c
index 00aeee0d5e45f..d14f5137379b9 100644
--- a/drivers/net/ethernet/mediatek/mtk_wed.c
+++ b/drivers/net/ethernet/mediatek/mtk_wed.c
@@ -41,7 +41,7 @@
 #define MTK_WED_RRO_QUE_CNT		8192
 #define MTK_WED_MIOD_ENTRY_CNT		128
 
-static struct mtk_wed_hw *hw_list[2];
+static struct mtk_wed_hw *hw_list[2] = {};
 static DEFINE_MUTEX(hw_lock);
 
 struct mtk_wed_flow_block_priv {
@@ -222,9 +222,13 @@ void mtk_wed_fe_reset(void)
 
 	for (i = 0; i < ARRAY_SIZE(hw_list); i++) {
 		struct mtk_wed_hw *hw = hw_list[i];
-		struct mtk_wed_device *dev = hw->wed_dev;
+		struct mtk_wed_device *dev;
 		int err;
 
+		if (!hw)
+			break;
+
+		dev = hw->wed_dev;
 		if (!dev || !dev->wlan.reset)
 			continue;
 
@@ -245,8 +249,12 @@ void mtk_wed_fe_reset_complete(void)
 
 	for (i = 0; i < ARRAY_SIZE(hw_list); i++) {
 		struct mtk_wed_hw *hw = hw_list[i];
-		struct mtk_wed_device *dev = hw->wed_dev;
+		struct mtk_wed_device *dev;
+
+		if (!hw)
+			break;
 
+		dev = hw->wed_dev;
 		if (!dev || !dev->wlan.reset_complete)
 			continue;
 
-- 
2.41.0