netdev - Re: [PATCH net] cls_bpf: don't decrement net's refcount when offload fails

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Message-ID: <9a326b7b-d80c-9d52-aba5-128dcd5b7778@iogearbox.net>
Date:   Mon, 27 Nov 2017 22:09:33 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Jakub Kicinski <jakub.kicinski@...ronome.com>,
        netdev@...r.kernel.org
Cc:     oss-drivers@...ronome.com, Cong Wang <xiyou.wangcong@...il.com>
Subject: Re: [PATCH net] cls_bpf: don't decrement net's refcount when offload
 fails

On 11/27/2017 08:11 PM, Jakub Kicinski wrote:
> When cls_bpf offload was added it seemed like a good idea to
> call cls_bpf_delete_prog() instead of extending the error
> handling path, since the software state is fully initialized
> at that point.  This handling of errors without jumping to
> the end of the function is error prone, as proven by later
> commit missing that extra call to __cls_bpf_delete_prog().
> 
> __cls_bpf_delete_prog() is now expected to be invoked with
> a reference on exts->net or the field zeroed out.  The call
> on the offload's error patch does not fullfil this requirement,
> leading to each error stealing a reference on net namespace.
> 
> Create a function undoing what cls_bpf_set_parms() did and
> use it from __cls_bpf_delete_prog() and the error path.
> 
> Fixes: aae2c35ec892 ("cls_bpf: use tcf_exts_get_net() before call_rcu()")
> Signed-off-by: Jakub Kicinski <jakub.kicinski@...ronome.com>
> Reviewed-by: Simon Horman <simon.horman@...ronome.com>

Fix looks good to me, thanks Jakub! If Dave wants to take
it directly:

Acked-by: Daniel Borkmann <daniel@...earbox.net>