netdev - Re: [PATCH net] net: sched: fix possible refcount leak in tc_chain_tmplt

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Date: Tue, 6 Jun 2023 11:33:36 +0200
From: Simon Horman <simon.horman@...igine.com>
To: Hangyu Hua <hbh25y@...il.com>
Cc: jhs@...atatu.com, xiyou.wangcong@...il.com, jiri@...nulli.us,
	davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
	pabeni@...hat.com, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] net: sched: fix possible refcount leak in
 tc_chain_tmplt_add()

On Tue, Jun 06, 2023 at 10:13:44AM +0800, Hangyu Hua wrote:
> On 5/6/2023 20:31, Simon Horman wrote:
> > On Mon, Jun 05, 2023 at 03:01:58PM +0800, Hangyu Hua wrote:
> > > try_module_get can be called in tcf_proto_lookup_ops. So if ops don't
> > > implement the corresponding function we should call module_put to drop
> > > the refcount.
> > 
> > Hi Hangyu Hua,
> > 
> > Is this correct even if try_module_get() is
> > not called via tcf_proto_lookup_ops() ?
> > 
> 
> tcf_proto_lookup_ops will return error if try_module_get() is not called in
> tcf_proto_lookup_ops(). I am not sure what you mean?

Thanks,

I think that answers my question.

My concern was if there is a situation where module_put() is
now called, but there was not in fact a reference that should
be released.

...