netdev - Re: [PATCH v2 net] net: Prevent invalid access to skb->prev in __qdisc_drop

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Message-ID: <2a2a645c-edc7-a492-f218-10ac22bdb590@gmail.com>
Date:   Thu, 29 Nov 2018 16:18:49 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Christoph Paasch <cpaasch@...le.com>,
        David Miller <davem@...emloft.net>
Cc:     netdev@...r.kernel.org,
        Prashant Bhole <bhole_prashant_q7@....ntt.co.jp>,
        Tyler Hicks <tyhicks@...onical.com>
Subject: Re: [PATCH v2 net] net: Prevent invalid access to skb->prev in
 __qdisc_drop_all



On 11/29/2018 04:01 PM, Christoph Paasch wrote:
> __qdisc_drop_all() accesses skb->prev to get to the tail of the
> segment-list.
> 
> With commit 68d2f84a1368 ("net: gro: properly remove skb from list")
> the skb-list handling has been changed to set skb->next to NULL and set
> the list-poison on skb->prev.
> 
> With that change, __qdisc_drop_all() will panic when it tries to
> dereference skb->prev.
> 

Reviewed-by: Eric Dumazet <edumazet@...gle.com>

Thanks !