Re: [ROSE] [AX25] 6.15.10 long term stable kernel oops

[F6BVP <f6bvp@free.fr>]

I tested the fix and validated it on different kernels versions.

All are doing fine : 6.14.11 , 6.15.11, 6.16.4

Congratulations and many thanks to Eric Dumazet for spending his time on
repairing AX25 mkiss serial connexions.

Hamradio fans will be able to continue experimenting with AX25 using
next Linux developments.

Bernard Pidoux
F6BVP / AI7BG
http://radiotelescope-lavillette.fr


Le 01/09/2025 à 14:04, Eric Dumazet a écrit :
> On Sat, Aug 30, 2025 at 4:37 PM F6BVP <f6bvp@free.fr> wrote:
>>
>> Here is a bad commit report by git bisect and the corresponding decoded
>> stack trace of kernel panic triggered when mkiss receives AX25 packet.
>>
>> All kernels following 6.14.11, i.e. starting with 6.15.1 until net-next
>> are affected by the issue.
>>
>> I would be pleased to check any patch correcting the issue.
>>
> 
> Thanks for the report.
> 
> At some point we will have to remove ax25, this has been quite broken
> for a long time.
> 
> Please try :
> 
> diff --git a/net/ax25/ax25_in.c b/net/ax25/ax25_in.c
> index 1cac25aca637..f2d66af86359 100644
> --- a/net/ax25/ax25_in.c
> +++ b/net/ax25/ax25_in.c
> @@ -433,6 +433,10 @@ static int ax25_rcv(struct sk_buff *skb, struct
> net_device *dev,
>   int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev,
>                    struct packet_type *ptype, struct net_device *orig_dev)
>   {
> +       skb = skb_share_check(skb, GFP_ATOMIC);
> +       if (!skb)
> +               return NET_RX_DROP;
> +
>          skb_orphan(skb);
> 
>          if (!net_eq(dev_net(dev), &init_net)) {