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Date:   Sat, 3 Dec 2022 11:46:18 -0800
From:   Cong Wang <xiyou.wangcong@gmail.com>
To:     Li Qiong <liqiong@nfschina.com>
Cc:     Jamal Hadi Salim <jhs@mojatatu.com>, Jiri Pirko <jiri@resnulli.us>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Yu Zhe <yuzhe@nfschina.com>
Subject: Re: [PATCH] net: sched: fix a error path in fw_change()
Message-ID: <Y4unik6y8a0MuoFt@pop-os.localdomain>
References: <20221201151532.25433-1-liqiong@nfschina.com>
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On Thu, Dec 01, 2022 at 11:15:32PM +0800, Li Qiong wrote:
> The 'pfp' pointer could be null if can't find the target filter.
> Check 'pfp' pointer and fix this error path.

Did you see any actual kernel crash? And do you have a reproducer too?
Please include them if you do.

> 
> Signed-off-by: Li Qiong <liqiong@nfschina.com>
> ---
>  net/sched/cls_fw.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
> index a32351da968c..b898e4a81146 100644
> --- a/net/sched/cls_fw.c
> +++ b/net/sched/cls_fw.c
> @@ -289,6 +289,12 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
>  			if (pfp == f)
>  				break;
>  
> +		if (!pfp) {
> +			tcf_exts_destroy(&fnew->exts);
> +			kfree(fnew);
> +			return err;


BTW, err is 0 here, you have to set some error here.

Thanks.