From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yannick Vignon <yannick.vignon@nxp.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 146/179] net: stmmac: Disable Tx queues when reconfiguring the interface
Date:   Mon, 29 Nov 2021 19:19:00 +0100
Message-Id: <20211129181723.756455199@linuxfoundation.org>
In-Reply-To: <20211129181718.913038547@linuxfoundation.org>
References: <20211129181718.913038547@linuxfoundation.org>
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From: Yannick Vignon <yannick.vignon@nxp.com>

[ Upstream commit b270bfe697367776eca2e6759a71d700fb8d82a2 ]

The Tx queues were not disabled in situations where the driver needed to
stop the interface to apply a new configuration. This could result in a
kernel panic when doing any of the 3 following actions:
* reconfiguring the number of queues (ethtool -L)
* reconfiguring the size of the ring buffers (ethtool -G)
* installing/removing an XDP program (ip l set dev ethX xdp)

Prevent the panic by making sure netif_tx_disable is called when stopping
an interface.

Without this patch, the following kernel panic can be observed when doing
any of the actions above:

Unable to handle kernel paging request at virtual address ffff80001238d040
[....]
 Call trace:
  dwmac4_set_addr+0x8/0x10
  dev_hard_start_xmit+0xe4/0x1ac
  sch_direct_xmit+0xe8/0x39c
  __dev_queue_xmit+0x3ec/0xaf0
  dev_queue_xmit+0x14/0x20
[...]
[ end trace 0000000000000002 ]---

Fixes: 5fabb01207a2d ("net: stmmac: Add initial XDP support")
Fixes: aa042f60e4961 ("net: stmmac: Add support to Ethtool get/set ring parameters")
Fixes: 0366f7e06a6be ("net: stmmac: add ethtool support for get/set channels")
Signed-off-by: Yannick Vignon <yannick.vignon@nxp.com>
Link: https://lore.kernel.org/r/20211124154731.1676949-1-yannick.vignon@oss.nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c18c05f78c208..1cf94248c2217 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3794,6 +3794,8 @@ int stmmac_release(struct net_device *dev)
 	struct stmmac_priv *priv = netdev_priv(dev);
 	u32 chan;
 
+	netif_tx_disable(dev);
+
 	if (device_may_wakeup(priv->device))
 		phylink_speed_down(priv->phylink, false);
 	/* Stop and disconnect the PHY */
-- 
2.33.0