From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH 5/5] net_sched: Fail if missing mandatory action
 operation methods
Date: Tue, 03 Dec 2013 11:48:34 -0500 (EST)
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From: Jamal Hadi Salim <jhs@mojatatu.com>
Date: Tue,  3 Dec 2013 09:23:19 -0500

> @@ -277,8 +277,10 @@ int tcf_register_action(struct tc_action_ops *act)
>  			return -EEXIST;
>  		}
>  	}
> -	act->next = NULL;
> -	*ap = act;
> +
> +	/* Must supply act, dump, cleanup and init */
> +	if (!act->act || !act->dump || !act->cleanup || !act->init)
> +		return -EINVAL;
>  
>  	/* Supply defaults */
>  	if (!act->lookup)

You are going to return with a lock held on error here.

I was going to tell you not to do these fixups so late in the
function, inside of the write lock, there is no reason for it.

You should do all of this operation handling at the top of
the function, before the write lock is taken.