netdev - Re: [PATCH net] sch_multiq: fix double free on init failure

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Date:   Tue, 29 Aug 2017 11:40:48 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
Cc:     netdev@...r.kernel.org, edumazet@...gle.com, jhs@...atatu.com,
        xiyou.wangcong@...il.com, jiri@...nulli.us,
        roopa@...ulusnetworks.com
Subject: Re: [PATCH net] sch_multiq: fix double free on init failure

On Tue, 2017-08-29 at 21:26 +0300, Nikolay Aleksandrov wrote:
> The below commit added a call to ->destroy() on init failure, but multiq
> still frees ->queues on error in init, but ->queues is also freed by
> ->destroy() thus we get double free and corrupted memory.
> 
> Very easy to reproduce (eth0 not multiqueue):
> $ tc qdisc add dev eth0 root multiq
> RTNETLINK answers: Operation not supported
> $ ip l add dumdum type dummy
> (crash)

> Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation")
> Signed-off-by: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
> ---
>  net/sched/sch_multiq.c | 3 ---
>  1 file changed, 3 deletions(-)
> 

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