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Subject: Re: [PATCH] xprtrdma: Make rpcrdma_sendctxs_destroy() more robust
From:   Chuck Lever <chuck.lever@oracle.com>
In-Reply-To: <20190107190806.GA6094@kadam>
Date:   Mon, 7 Jan 2019 16:25:19 -0500
Cc:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Jeff Layton <jlayton@kernel.org>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        kernel-janitors@vger.kernel.org
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Message-Id: <E3C7A7BA-DECD-4EF6-96D8-A43681E56081@oracle.com>
References: <20190107190806.GA6094@kadam>
To:     Dan Carpenter <dan.carpenter@oracle.com>
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk


> On Jan 7, 2019, at 2:08 PM, Dan Carpenter <dan.carpenter@oracle.com> =
wrote:
>=20
> There was a double free in the error handling here recently.  It was
> a bit subtle which function was supposed to call =
rpcrdma_sendctxs_destroy()
> so it was called in both.
>=20
> This patch makes it so we can call rpcrdma_sendctxs_destroy() twice
> in a row without crashing.

Belt-and-braces. I think the other patch "must" be applied, and this
one "should" be applied.

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


> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> net/sunrpc/xprtrdma/verbs.c | 3 +++
> 1 file changed, 3 insertions(+)
>=20
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 7749a2bf6887..d05f4885548d 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -802,9 +802,12 @@ static void rpcrdma_sendctxs_destroy(struct =
rpcrdma_buffer *buf)
> {
> 	unsigned long i;
>=20
> +	if (!buf->rb_sc_ctxs)
> +		return;
> 	for (i =3D 0; i <=3D buf->rb_sc_last; i++)
> 		kfree(buf->rb_sc_ctxs[i]);
> 	kfree(buf->rb_sc_ctxs);
> +	buf->rb_sc_ctxs =3D NULL;
> }
>=20
> static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct =
rpcrdma_ia *ia)
> --=20
> 2.17.1
>=20

--
Chuck Lever