linux-kernel - Re: [REPORT] Null pointer deref in net/core/dev.c on PowerPC

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Message-ID: <e9f4abee-b132-440f-a50e-bced0868b5a7@linux.ibm.com>
Date: Wed, 17 Dec 2025 23:33:04 +0530
From: Aditya Gupta <adityag@...ux.ibm.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Subject: Re: [REPORT] Null pointer deref in net/core/dev.c on PowerPC

On 17/12/25 20:11, Eric Dumazet wrote:

> <...snip...>
>
> I will send the following fix, thanks.
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 9094c0fb8c68..36dc5199037e 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -4241,9 +4241,11 @@ static inline int __dev_xmit_skb(struct sk_buff
> *skb, struct Qdisc *q,
>                  int count = 0;
>
>                  llist_for_each_entry_safe(skb, next, ll_list, ll_node) {
> -                       prefetch(next);
> -                       prefetch(&next->priority);
> -                       skb_mark_not_on_list(skb);
> +                       if (next) {
> +                               prefetch(next);
> +                               prefetch(&next->priority);
> +                               skb_mark_not_on_list(skb);
> +                       }
>                          rc = dev_qdisc_enqueue(skb, q, &to_free, txq);
>                          count++;
>                  }

Thanks for the quick fix Eric !

- Aditya G