[PATCH net] net: stmmac: Disable Tx queues when reconfiguring the interface

Subsystems: networking drivers, stmmac ethernet driver, the rest

STALE1722d

5 messages, 3 authors, 2021-11-24 · open the first message on its own page

[PATCH net] net: stmmac: Disable Tx queues when reconfiguring the interface

From: Yannick Vignon <hidden>
Date: 2021-11-23 18:55:40

From: Yannick Vignon <redacted>

The Tx queues were not disabled in cases 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 loading
an XDP program:

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: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Signed-off-by: Yannick Vignon <redacted>
---
 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 f12097c8a485..748195697e5a 100644
--- 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 */
-- 
2.25.1

Re: [PATCH net] net: stmmac: Disable Tx queues when reconfiguring the interface

From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-11-24 04:07:53

On Tue, 23 Nov 2021 19:54:48 +0100 Yannick Vignon wrote:
From: Yannick Vignon <redacted>

The Tx queues were not disabled in cases 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 loading
an XDP program:

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: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Signed-off-by: Yannick Vignon <redacted>
Fixes tag: Fixes: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Has these problem(s):
	- Target SHA1 does not exist

Re: [PATCH net] net: stmmac: Disable Tx queues when reconfiguring the interface

From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-11-24 10:06:36

On Tue, Nov 23, 2021 at 08:07:51PM -0800, Jakub Kicinski wrote:
On Tue, 23 Nov 2021 19:54:48 +0100 Yannick Vignon wrote:
quoted
From: Yannick Vignon <redacted>

The Tx queues were not disabled in cases 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 loading
an XDP program:

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: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Signed-off-by: Yannick Vignon <redacted>
Fixes tag: Fixes: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Has these problem(s):
	- Target SHA1 does not exist
You caught him backporting! Although I agree, things sent to the "net"
tree should also be tested against the "net" tree.

Re: [PATCH net] net: stmmac: Disable Tx queues when reconfiguring the interface

From: Yannick Vignon <hidden>
Date: 2021-11-24 12:12:28

On 11/24/2021 11:06 AM, Vladimir Oltean wrote:
On Tue, Nov 23, 2021 at 08:07:51PM -0800, Jakub Kicinski wrote:
quoted
On Tue, 23 Nov 2021 19:54:48 +0100 Yannick Vignon wrote:
quoted
From: Yannick Vignon <redacted>

The Tx queues were not disabled in cases 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 loading
an XDP program:

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: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Signed-off-by: Yannick Vignon <redacted>
Fixes tag: Fixes: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Has these problem(s):
	- Target SHA1 does not exist
You caught him backporting! Although I agree, things sent to the "net"
tree should also be tested against the "net" tree.
That would be more like forward-porting in this case, since I first 
fixed the issue on an older 5.10 kernel :)
And yes, I did reproduce the bug and confirm the fix on the tip of the 
netdev branch yesterday before sending the patch. But I guess I looked 
at the wrong branch when adding the Fixes tag...

Will post a V2 to fix the Fixes tag.

Re: [PATCH net] net: stmmac: Disable Tx queues when reconfiguring the interface

From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-11-24 12:42:07

On Wed, Nov 24, 2021 at 01:10:55PM +0100, Yannick Vignon wrote:
On 11/24/2021 11:06 AM, Vladimir Oltean wrote:
quoted
On Tue, Nov 23, 2021 at 08:07:51PM -0800, Jakub Kicinski wrote:
quoted
On Tue, 23 Nov 2021 19:54:48 +0100 Yannick Vignon wrote:
quoted
From: Yannick Vignon <redacted>

The Tx queues were not disabled in cases 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 loading
an XDP program:

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: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Signed-off-by: Yannick Vignon <redacted>
Fixes tag: Fixes: 78cb988d36b6 ("net: stmmac: Add initial XDP support")
Has these problem(s):
	- Target SHA1 does not exist
You caught him backporting! Although I agree, things sent to the "net"
tree should also be tested against the "net" tree.
That would be more like forward-porting in this case, since I first fixed
the issue on an older 5.10 kernel :)
XDP for stmmac isn't in v5.10, so backporting is what it is.
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