Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <fb24ef9ad94f8b052407c5bdd4e3815675b89213.camel@tsoy.me>
Subject: Re: [PATCH 5.10 35/38] rtnetlink: Fix missing error code in
 rtnl_bridge_notify()
From:   Alexander Tsoy <alexander@tsoy.me>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, Abaci Robot <abaci@linux.alibaba.com>,
        Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Date:   Sat, 19 Jun 2021 02:58:28 +0300
In-Reply-To: <20210616152836.507544876@linuxfoundation.org>
References: <20210616152835.407925718@linuxfoundation.org>
         <20210616152836.507544876@linuxfoundation.org>
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.40.1 
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: puleglot@puleglot.ru
Precedence: bulk

В Ср, 16/06/2021 в 17:33 +0200, Greg Kroah-Hartman пишет:
> From: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> 
> [ Upstream commit a8db57c1d285c758adc7fb43d6e2bad2554106e1 ]
> 
> The error code is missing in this code scenario, add the error code
> '-EINVAL' to the return value 'err'.
> 
> Eliminate the follow smatch warning:
> 
> net/core/rtnetlink.c:4834 rtnl_bridge_notify() warn: missing error code
> 'err'.

This patch breaks systemd-resolved. It is 100% reproducible on two of
my systems, but there are also systems where I cannot reproduce it. The
problem manifests itself as SERVFAIL on every DNS query.

Just reverting this patch from 5.10.45 fixes the problem for me.

> 
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  net/core/rtnetlink.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index eae8e87930cd..83894723ebee 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -4842,8 +4842,10 @@ static int rtnl_bridge_notify(struct net_device
> *dev)
>         if (err < 0)
>                 goto errout;
>  
> -       if (!skb->len)
> +       if (!skb->len) {
> +               err = -EINVAL;
>                 goto errout;
> +       }
>  
>         rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
>         return 0;