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;
Date:   Fri, 21 Jan 2022 08:13:11 -0800
From:   Stephen Hemminger <stephen@networkplumber.org>
To:     ycaibb <ycaibb@gmail.com>
Cc:     davem@davemloft.net, yoshfuji@linux-ipv6.org, dsahern@kernel.org,
        kuba@kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: missing lock releases in ipmr_base.c
Message-ID: <20220121081311.2518068f@hermes.local>
In-Reply-To: <20220121032210.5829-1-ycaibb@gmail.com>
References: <20220121032210.5829-1-ycaibb@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Fri, 21 Jan 2022 11:22:10 +0800
ycaibb <ycaibb@gmail.com> wrote:

> From: Ryan Cai <ycaibb@gmail.com>
> 
> In method mr_mfc_seq_idx, the lock it->lock and rcu_read_lock are not released when pos-- == 0 is true.
> 
> Signed-off-by: Ryan Cai <ycaibb@gmail.com>
> ---
>  net/ipv4/ipmr_base.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/ipv4/ipmr_base.c b/net/ipv4/ipmr_base.c
> index aa8738a91210..c4a247024c85 100644
> --- a/net/ipv4/ipmr_base.c
> +++ b/net/ipv4/ipmr_base.c
> @@ -154,6 +154,7 @@ void *mr_mfc_seq_idx(struct net *net,
>  	it->cache = &mrt->mfc_cache_list;
>  	list_for_each_entry_rcu(mfc, &mrt->mfc_cache_list, list)
>  		if (pos-- == 0)
> +			rcu_read_unlock();
>  			return mfc;
>  	rcu_read_unlock();
>  
> @@ -161,6 +162,7 @@ void *mr_mfc_seq_idx(struct net *net,
>  	it->cache = &mrt->mfc_unres_queue;
>  	list_for_each_entry(mfc, it->cache, list)
>  		if (pos-- == 0)
> +			spin_unlock_bh(it->lock);
>  			return mfc;
>  	spin_unlock_bh(it->lock);
>  

Another buggy patch, perhaps you write python or research papers?