MIME-Version: 1.0
References: <tencent_CE0F8701456CB89F92C73F28480EF3552E06@qq.com>
In-Reply-To: <tencent_CE0F8701456CB89F92C73F28480EF3552E06@qq.com>
From:   Anna Schumaker <anna.schumaker@netapp.com>
Date:   Thu, 16 Dec 2021 11:39:39 -0500
Message-ID: <CAFX2Jfk-gH5V2PL3UkSw=QLDDuzSgbKuzUeh8-ir-VpO0BzMpg@mail.gmail.com>
Subject: Re: [PATCH] nfs: nfs4clinet: check the return value of kstrdup()
To:     Xiaoke Wang <xkernel.wang@foxmail.com>
Cc:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Xiaoke,

On Mon, Dec 13, 2021 at 2:54 AM Xiaoke Wang <xkernel.wang@foxmail.com> wrote:
>
> kstrdup() returns NULL when some internal memory errors happen, it is
> better to check the return value of it so to catch the memory error in
> time.
>
> Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
> ---
>  fs/nfs/nfs4client.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
> index af57332..89f13e0 100644
> --- a/fs/nfs/nfs4client.c
> +++ b/fs/nfs/nfs4client.c
> @@ -1372,5 +1372,8 @@ int nfs4_update_server(struct nfs_server *server, const char *hostname,
>                 server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL);
>         nfs_server_insert_lists(server);
>
> +       if (server->nfs_client->cl_hostname == NULL)
> +               return -ENOMEM;
> +

Checking the return of kstrdup() makes sense, but I think this should
right after the kstrdup() call and still under that if block.

Anna

>         return nfs_probe_destination(server);
>  }
> --