try_module_get will be called in tcf_proto_lookup_ops. So module_put needs
to be called to drop the refcount if ops don't implement the required
function.

Fixes: 9f407f1768d3 ("net: sched: introduce chain templates")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
---
	
	v2: fix the patch description.

 net/sched/cls_api.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 2621550bfddc..92bfb892e638 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -2952,6 +2952,7 @@ static int tc_chain_tmplt_add(struct tcf_chain *chain, struct net *net,
 		return PTR_ERR(ops);
 	if (!ops->tmplt_create || !ops->tmplt_destroy || !ops->tmplt_dump) {
 		NL_SET_ERR_MSG(extack, "Chain templates are not supported with specified classifier");
+		module_put(ops->owner);
 		return -EOPNOTSUPP;
 	}
 
-- 
2.34.1

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Wed,  7 Jun 2023 10:23:01 +0800 you wrote:
> try_module_get will be called in tcf_proto_lookup_ops. So module_put needs
> to be called to drop the refcount if ops don't implement the required
> function.
> 
> Fixes: 9f407f1768d3 ("net: sched: introduce chain templates")
> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
> 
> [...]

Here is the summary with links:
  - [net,v2] net: sched: fix possible refcount leak in tc_chain_tmplt_add()
    https://git.kernel.org/netdev/net/c/44f8baaf230c

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
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On Wed, Jun 07, 2023 at 10:23:01AM +0800, Hangyu Hua wrote:
> try_module_get will be called in tcf_proto_lookup_ops. So module_put needs
> to be called to drop the refcount if ops don't implement the required
> function.
> 
> Fixes: 9f407f1768d3 ("net: sched: introduce chain templates")

Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>

> Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
> ---
> 	
> 	v2: fix the patch description.
> 
>  net/sched/cls_api.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
> index 2621550bfddc..92bfb892e638 100644
> --- a/net/sched/cls_api.c
> +++ b/net/sched/cls_api.c
> @@ -2952,6 +2952,7 @@ static int tc_chain_tmplt_add(struct tcf_chain *chain, struct net *net,
>  		return PTR_ERR(ops);
>  	if (!ops->tmplt_create || !ops->tmplt_destroy || !ops->tmplt_dump) {
>  		NL_SET_ERR_MSG(extack, "Chain templates are not supported with specified classifier");
> +		module_put(ops->owner);
>  		return -EOPNOTSUPP;
>  	}
>  
> -- 
> 2.34.1
>