[PATCH net v3] net: b44: set pause params only when interface is up

[PATCH net v3] net: b44: set pause params only when interface is up

[Peter Münster]

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Hi,

This patch fixes a kernel panic when using netifd.

Kind regards,
-- 
           Peter

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b44_free_rings() accesses b44::rx_buffers (and ::tx_buffers)
unconditionally, but b44::rx_buffers is only valid when the
device is up (they get allocated in b44_open(), and deallocated
again in b44_close()), any other time these is just a NULL pointers.

So if you try to change the pause params while the network interface
is disabled/administratively down, everything explodes (which likely
netifd tries to do).

Link: https://github.com/openwrt/openwrt/issues/13789
Fixes: 1da177e4c3f4 (Linux-2.6.12-rc2)
Cc: stable@vger.kernel.org
Reported-by: Peter Münster <pm@a16n.net>
Suggested-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Vaclav Svoboda <svoboda@neng.cz>
Tested-by: Peter Münster <pm@a16n.net>
Signed-off-by: Peter Münster <pm@a16n.net>
---
 drivers/net/ethernet/broadcom/b44.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c
index 3e4fb3c3e834..1be6d14030bc 100644
--- a/drivers/net/ethernet/broadcom/b44.c
+++ b/drivers/net/ethernet/broadcom/b44.c
@@ -2009,12 +2009,14 @@ static int b44_set_pauseparam(struct net_device *dev,
 		bp->flags |= B44_FLAG_TX_PAUSE;
 	else
 		bp->flags &= ~B44_FLAG_TX_PAUSE;
-	if (bp->flags & B44_FLAG_PAUSE_AUTO) {
-		b44_halt(bp);
-		b44_init_rings(bp);
-		b44_init_hw(bp, B44_FULL_RESET);
-	} else {
-		__b44_set_flow_ctrl(bp, bp->flags);
+	if (netif_running(dev)) {
+		if (bp->flags & B44_FLAG_PAUSE_AUTO) {
+			b44_halt(bp);
+			b44_init_rings(bp);
+			b44_init_hw(bp, B44_FULL_RESET);
+		} else {
+			__b44_set_flow_ctrl(bp, bp->flags);
+		}
 	}
 	spin_unlock_irq(&bp->lock);
 
-- 
2.35.3


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Re: [PATCH net v3] net: b44: set pause params only when interface is up

[Andrew Lunn]

On Fri, Apr 19, 2024 at 10:44:28PM +0200, Peter Münster wrote:
> Hi,
> 
> This patch fixes a kernel panic when using netifd.
> 
> Kind regards,
> -- 
>            Peter

Still above the --- . Don't use attachments.

The best way to send patches is

git format-patch

followed by

git send email

https://docs.kernel.org/process/submitting-patches.html#the-canonical-patch-format

Alternatively, look at b4:

https://b4.docs.kernel.org/en/latest/contributor/prep.html

Interestingly, patchwork does seemed to of extracted the patch:

https://patchwork.kernel.org/project/netdevbpf/patch/87o7a5yteb.fsf@a16n.net/

So it could be the patch can be applied as it is. Lets see what Jakub
says.

Anyway:

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

We are picky about things like this because there are a lot of patches
flying around, and we need to be efficient at applying them. So we
want patches in a specific format. It takes a little bit of time to
learn to do it correct, but once you use the tools correctly it
becomes simple as a developer and efficient for those receiving the
patches.

     Andrew

Re: [PATCH net v3] net: b44: set pause params only when interface is up

[Peter Münster]

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On Fri, Apr 19 2024, Andrew Lunn wrote:

> Still above the --- . Don't use attachments.

Ah, ok, sorry.


> Lets see what Jakub says.

Ok, so I should wait before sending v4?


> Reviewed-by: Andrew Lunn <andrew@lunn.ch>

Another line to attach to the patch for v4?


> We are picky about things like this

No problem, I fully understand.

-- 
           Peter

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