Re: [PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()

From: Chuck Lever <chuck.lever@oracle.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Bruce Fields <bfields@fieldses.org>,
	Jeff Layton <jlayton@kernel.org>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna.schumaker@netapp.com>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH 2/2] xprtrdma: Double free in rpcrdma_sendctxs_create()
Date: Sat, 05 Jan 2019 16:24:45 +0000	[thread overview]
Message-ID: <0CEEB35A-2083-4888-9035-8A9ADF22E8E3@oracle.com> (raw)
In-Reply-To: <20190105130648.GC3288@kadam>

> On Jan 5, 2019, at 8:06 AM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> 
> The clean up is handled by the caller, rpcrdma_buffer_create(), so this
> call to rpcrdma_sendctxs_destroy() leads to a double free.

True. This fix is adequate, but I'm wondering if rpcrdma_sendctxs_destroy
should be made more careful about being called twice. Hm.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>

> Fixes: ae72950abf99 ("xprtrdma: Add data structure to manage RDMA Send arguments")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> net/sunrpc/xprtrdma/verbs.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 3dde05892c8e..4994e75945b8 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -845,17 +845,13 @@ static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
> 	for (i = 0; i <= buf->rb_sc_last; i++) {
> 		sc = rpcrdma_sendctx_create(&r_xprt->rx_ia);
> 		if (!sc)
> -			goto out_destroy;
> +			return -ENOMEM;
> 
> 		sc->sc_xprt = r_xprt;
> 		buf->rb_sc_ctxs[i] = sc;
> 	}
> 
> 	return 0;
> -
> -out_destroy:
> -	rpcrdma_sendctxs_destroy(buf);
> -	return -ENOMEM;
> }
> 
> /* The sendctx queue is not guaranteed to have a size that is a
> -- 
> 2.17.1
> 

--
Chuck Lever