netdev - Re: [PATCH] nfsd: fix double fget() bug in __write_ports

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Message-ID: <9279444f-b113-41ad-afaa-c6b550104906@kili.mountain>
Date: Wed, 31 May 2023 10:58:51 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: NeilBrown <neilb@...e.de>
Cc: Stanislav Kinsbursky <skinsbursky@...allels.com>,
	Chuck Lever <chuck.lever@...cle.com>,
	Jeff Layton <jlayton@...nel.org>,
	Trond Myklebust <trond.myklebust@...merspace.com>,
	Anna Schumaker <anna@...nel.org>,
	"J. Bruce Fields" <bfields@...hat.com>, linux-nfs@...r.kernel.org,
	netdev@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] nfsd: fix double fget() bug in __write_ports_addfd()

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