From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966635AbdKPSPD (ORCPT ); Thu, 16 Nov 2017 13:15:03 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:41936 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966605AbdKPSOl (ORCPT ); Thu, 16 Nov 2017 13:14:41 -0500 Subject: Re: [PATCH] net/smc: Fix preinitialization of buf_desc in __smc_buf_create() To: Geert Uytterhoeven , "David S . Miller" Cc: Arnd Bergmann , linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1510831373-31768-1-git-send-email-geert@linux-m68k.org> From: Ursula Braun Date: Thu, 16 Nov 2017 19:14:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1510831373-31768-1-git-send-email-geert@linux-m68k.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 17111618-0012-0000-0000-0000058E2FDC X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17111618-0013-0000-0000-00001908F2FC Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-11-16_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1711160243 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/16/2017 12:22 PM, Geert Uytterhoeven wrote: > With gcc-4.1.2: > > net/smc/smc_core.c: In function ‘__smc_buf_create’: > net/smc/smc_core.c:567: warning: ‘bufsize’ may be used uninitialized in this function > > Indeed, if the for-loop is never executed, bufsize is used > uninitialized. In addition, buf_desc is stored for later use, while it > is still a NULL pointer. > > Before, error handling was done by checking if buf_desc is non-NULL. > The cleanup changed this to an error check, but forgot to update the > preinitialization of buf_desc to an error pointer. > > Update the preinitializatin of buf_desc to fix this. > > Fixes: b33982c3a6838d13 ("net/smc: cleanup function __smc_buf_create()") > Signed-off-by: Geert Uytterhoeven > --- > I don't know if this can ever happen, but the old code handled it. The for-loop is at least executed once; thus there is no real problem. Nevertheless the warning is ugly, and the current initialization with NULL meaningless after the smc_buf cleanup. Therefore I add your patch to my list of coming smc patches. Thanks! > --- > net/smc/smc_core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c > index 2578fbd95664af84..453c54467082d93f 100644 > --- a/net/smc/smc_core.c > +++ b/net/smc/smc_core.c > @@ -562,7 +562,7 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_rmb) > { > struct smc_connection *conn = &smc->conn; > struct smc_link_group *lgr = conn->lgr; > - struct smc_buf_desc *buf_desc = NULL; > + struct smc_buf_desc *buf_desc = ERR_PTR(-ENOMEM); > struct list_head *buf_list; > int bufsize, bufsize_short; > int sk_buf_size; >