Subject: Re: [PATCH] net: missing lock releases in ipmr_base.c

From: Stephen Hemminger <[email-masked]>
Date: Fri, 21 Jan 2022 08:13:11 -0800

On Fri, 21 Jan 2022 11:22:10 +0800
ycaibb <[email-masked]> wrote:

> From: Ryan Cai <[email-masked]>
> 
> 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 <[email-masked]>
> ---
>  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?