net: stmmac: Disable Tx queues when reconfiguring the interface

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: ffc6ee3fdea55 ("net: stmmac: Add initial XDP support")
Fixes: c06ce0a13f5af ("net: stmmac: Add support to Ethtool get/set ring parameters")
Fixes: e6744ea6e5815 ("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>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index f12097c8a4850619085cae823b34fba6a961547f..748195697e5a09bf09b7a3206ece0ec19807232c 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -3802,6 +3802,8 @@ 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 */