[PATCH net v4] net: b44: set pause params only when interface is up

[PATCH net v4] net: b44: set pause params only when interface is up

[Peter Münster]

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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 are 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>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
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 v4] net: b44: set pause params only when interface is up

[Michael Chan]

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On Wed, Apr 24, 2024 at 6:51 AM Peter Münster <pm@a16n.net> wrote:
>
> 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 are 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>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Peter Münster <pm@a16n.net>

Reviewed-by: Michael Chan <michael.chan@broadcom.com>

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[PATCH net v4] net: b44: set pause params only when interface is up

[Hariprasad Kelam]

Understood, this patch fixes the panic issue.
 See inline for few comments,

> 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 are
> 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>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> 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);
> +		}
>  	}
The actual register config to enable pause frame is protected with "netif_running", does driver need to
reject the request if interface is down.
Otherwise, there is mismatch if someone reads pause frame status (b44_get_pauseparam).


Thanks,
Hariprasad k
>  	spin_unlock_irq(&bp->lock);
> 
> --
> 2.35.3

Re: [PATCH net v4] net: b44: set pause params only when interface is up

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 24 Apr 2024 15:51:52 +0200 you wrote:
> 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 are 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).
> 
> [...]

Here is the summary with links:
  - [net,v4] net: b44: set pause params only when interface is up
    https://git.kernel.org/netdev/net/c/e3eb7dd47bd4

You are awesome, thank you!
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