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Date:   Wed, 31 May 2023 10:58:51 +0300
From:   Dan Carpenter <dan.carpenter@linaro.org>
To:     NeilBrown <neilb@suse.de>
Cc:     Stanislav Kinsbursky <skinsbursky@parallels.com>,
        Chuck Lever <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@kernel.org>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna@kernel.org>,
        "J. Bruce Fields" <bfields@redhat.com>, linux-nfs@vger.kernel.org,
        netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] nfsd: fix double fget() bug in __write_ports_addfd()
Message-ID: <9279444f-b113-41ad-afaa-c6b550104906@kili.mountain>
References: <9c90e813-c7fb-4c90-b52b-131481640a78@kili.mountain>
 <168548566376.23533.14778348024215909777@noble.neil.brown.name>
 <58fd7e35-ba6c-432e-8e02-9c5476c854b4@kili.mountain>
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On Wed, May 31, 2023 at 10:48:09AM +0300, Dan Carpenter wrote:
>  	err = nfsd_create_serv(net);
>  	if (err != 0)
> -		return err;
> +		goto out_put_sock;
>  
> -	err = svc_addsock(nn->nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT, cred);
> +	err = svc_addsock(nn->nfsd_serv, so, buf, SIMPLE_TRANSACTION_LIMIT, cred);
> +	if (err)
> +		goto out_put_net;

Oops.  This change is wrong.  svc_addsock() actually does return
positive values on success.

>  
> -	if (err >= 0 &&
> -	    !nn->nfsd_serv->sv_nrthreads && !xchg(&nn->keep_active, 1))
> +	if (!nn->nfsd_serv->sv_nrthreads && !xchg(&nn->keep_active, 1))
>  		svc_get(nn->nfsd_serv);
>  
>  	nfsd_put(net);
> +	return 0;

Also wrong (same bug).

> +
> +out_put_net:
> +	nfsd_put(net);
> +out_put_sock:
> +	sockfd_put(so);
>  	return err;
>  }

regards,
dan carpenter