From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EB32EC43603 for ; Wed, 4 Dec 2019 18:43:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEB1E20675 for ; Wed, 4 Dec 2019 18:43:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="S6ZibFY0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728587AbfLDSn5 (ORCPT ); Wed, 4 Dec 2019 13:43:57 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:49246 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728244AbfLDSn5 (ORCPT ); Wed, 4 Dec 2019 13:43:57 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xB4IY6on074545; Wed, 4 Dec 2019 18:43:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=iW3p+lMiFZuhMFDcuCH3k9CwOvQRI86to7kQ5iH1Rq4=; b=S6ZibFY0lW8ejK3kFSiyqf7Vpdd9fY6E2NTXRsRhCYThgfMRpGz8vcMPSFGZaruvC3hZ jgEKyGaGOquOpKxZMjUgyDcx8BXEJ2JNNRm4xm2qHrD6+q11Gqy4YlRlIW3ZX9krO23X aIaPgqywANWpQVonrZ0vS/12Gs6nvGNhS0RUsS1cxtoJjZ1FHy7F7XWi1GSgzka2Mc1T jH7gnKqm2XA1B3+6+13SGIAUiwXMdTvIUCr/30qGFGcellsnE2VPvbo6ta3MF8V3LZ6+ 06lwveWeAZ/Tf77qBCLVQ5mo600cJW8BB9jWoL2Fn5ZQgb+cXqZdWzjmW6MGydu08aji qw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2wkh2rg5c5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 04 Dec 2019 18:43:16 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xB4IhFsD014723; Wed, 4 Dec 2019 18:43:16 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 2wp17en7cr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 04 Dec 2019 18:43:15 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xB4Igt7S024219; Wed, 4 Dec 2019 18:42:56 GMT Received: from kadam (/129.205.23.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 04 Dec 2019 10:42:54 -0800 Date: Wed, 4 Dec 2019 21:42:47 +0300 From: Dan Carpenter To: Steven Rostedt Cc: Ingo Molnar , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH] Silence an uninitialized variable warning Message-ID: <20191204184247.GG1765@kadam> References: <20191126121934.kuolgbm55dirfbay@kili.mountain> <20191204092640.692c95af@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191204092640.692c95af@gandalf.local.home> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9461 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912040151 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9461 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-1912040150 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 04, 2019 at 09:26:40AM -0500, Steven Rostedt wrote: > On Tue, 26 Nov 2019 15:19:34 +0300 > Dan Carpenter wrote: > > > Smatch complains that "ret" could be uninitialized if we don't enter the > > loop. I don't know if that's possible, but it's nicer to return a > > literal zero instead. > > > > Signed-off-by: Dan Carpenter > > --- > > kernel/trace/trace_syscalls.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c > > index 73140d80dd46..63528f458826 100644 > > --- a/kernel/trace/trace_syscalls.c > > +++ b/kernel/trace/trace_syscalls.c > > @@ -286,7 +286,7 @@ static int __init syscall_enter_define_fields(struct trace_event_call *call) > > offset += sizeof(unsigned long); > > } > > > > - return ret; > > + return 0; > > } > > > > static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) > > The current code has this: > > static int __init syscall_enter_define_fields(struct trace_event_call *call) > { > struct syscall_trace_enter trace; > struct syscall_metadata *meta = call->data; > int ret; > int i; > int offset = offsetof(typeof(trace), args); > > ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr), > FILTER_OTHER); In linux-next this ret = trace_define_field() assignment is removed. That was commit 60fdad00827c ("ftrace: Rework event_create_dir()"). > if (ret) > return ret; > > for (i = 0; i < meta->nb_args; i++) { > ret = trace_define_field(call, meta->types[i], > meta->args[i], offset, > sizeof(unsigned long), 0, > FILTER_OTHER); > offset += sizeof(unsigned long); > } > > return ret; > } > > > How can ret possibly be uninitialized? I should have written this commit more carefully and verified whether meta->nb_args can actually be zero instead of just assuming it was a false positive... regards, dan carpenter