openwrt/target/linux/bcm63xx/patches-5.4/047-bcm63xx_enet-fix-kernel-panic.patch

From ca6be00ca1d3a2f5b8794894e2dae175e63768f5 Mon Sep 17 00:00:00 2001
From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
Date: Tue, 16 Feb 2021 16:23:08 +0800
Subject: [PATCH] bcm63xx_enet: Fix sporadic kernel panic

In ndo_stop functions, netdev_completed_queue() is called during forced
tx reclaim, after netdev_reset_queue(). This may trigger kernel panic if
there is any tx skb left.

This patch moves netdev_reset_queue() to after tx reclaim, so BQL can
complete successfully then reset.

Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com>
---
 drivers/net/ethernet/broadcom/bcm63xx_enet.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
@@ -1193,7 +1193,6 @@ static int bcm_enet_stop(struct net_devi
 	kdev = &priv->pdev->dev;
 
 	netif_stop_queue(dev);
-	netdev_reset_queue(dev);
 	napi_disable(&priv->napi);
 	if (priv->has_phy)
 		phy_stop(dev->phydev);
@@ -1232,6 +1231,9 @@ static int bcm_enet_stop(struct net_devi
 	if (priv->has_phy)
 		phy_disconnect(dev->phydev);
 
+	/* reset BQL after forced tx reclaim to not kernel panic */
+	netdev_reset_queue(dev);
+
 	return 0;
 }
 
@@ -2348,7 +2350,6 @@ static int bcm_enetsw_stop(struct net_de
 
 	del_timer_sync(&priv->swphy_poll);
 	netif_stop_queue(dev);
-	netdev_reset_queue(dev);
 	napi_disable(&priv->napi);
 	del_timer_sync(&priv->rx_timeout);
 
@@ -2376,6 +2377,9 @@ static int bcm_enetsw_stop(struct net_de
 		free_irq(priv->irq_tx, dev);
 	free_irq(priv->irq_rx, dev);
 
+	/* reset BQL after forced tx reclaim to not kernel panic */
+	netdev_reset_queue(dev);
+
 	return 0;
 }