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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 972B9C3279B for ; Tue, 10 Jul 2018 22:58:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C60C2098B for ; Tue, 10 Jul 2018 22:58:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C60C2098B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732298AbeGJW7p (ORCPT ); Tue, 10 Jul 2018 18:59:45 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:43856 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732264AbeGJW7p (ORCPT ); Tue, 10 Jul 2018 18:59:45 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8A31481663EE; Tue, 10 Jul 2018 22:58:27 +0000 (UTC) Received: from krava (ovpn-204-33.brq.redhat.com [10.40.204.33]) by smtp.corp.redhat.com (Postfix) with SMTP id C3D2B1C4C3; Tue, 10 Jul 2018 22:58:25 +0000 (UTC) Date: Wed, 11 Jul 2018 00:58:24 +0200 From: Jiri Olsa To: William Cohen Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org, alexander.shishkin@linux.intel.com, namhyung@kernel.org Subject: Re: [PATCH] Check jvmti_agent snprintf return value to avoid build failures with GCC-8.1.1 Message-ID: <20180710225824.GA11928@krava> References: <20180710182716.21801-1-wcohen@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180710182716.21801-1-wcohen@redhat.com> User-Agent: Mutt/1.10.0 (2018-05-17) X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 22:58:27 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 22:58:27 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jolsa@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 10, 2018 at 02:27:16PM -0400, William Cohen wrote: > Newer versions of GCC perform static analysis to determine whether > string truncation is possible with functions such as snprintf and > provide a warning if truncation could occur. The make for > jvmti_agent.c uses the compiler option that treats any compiler > warnings as compiler errors. For GCC-8.1.1 in Fedora 28 this causes > the build to fail. The return value of the snprint is now checked to > ensure snprintf produced a NULL-terminated string. If the string for > the path is invalid, the code does attempt to use the string. hi, I posted fix for this recently: https://lore.kernel.org/lkml/20180702134202.17745-1-jolsa@kernel.org/ it also covers the perf_regs.c, which was failing with gcc8 for me should be pulled in soon thanks, jirka > > Signed-off-by: William Cohen > --- > tools/perf/jvmti/jvmti_agent.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/jvmti/jvmti_agent.c b/tools/perf/jvmti/jvmti_agent.c > index 0c6d1002b524..30f14eafe4b3 100644 > --- a/tools/perf/jvmti/jvmti_agent.c > +++ b/tools/perf/jvmti/jvmti_agent.c > @@ -227,7 +227,7 @@ void *jvmti_open(void) > { > char dump_path[PATH_MAX]; > struct jitheader header; > - int fd; > + int retlen, fd; > FILE *fp; > > init_arch_timestamp(); > @@ -249,7 +249,10 @@ void *jvmti_open(void) > /* > * jitdump file name > */ > - snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", jit_path, getpid()); > + retlen = snprintf(dump_path, PATH_MAX, "%s/jit-%i.dump", > + jit_path, getpid()); > + if (retlen <= 0 || ((int) sizeof(dump_path)) <= retlen) > + return NULL; > > fd = open(dump_path, O_CREAT|O_TRUNC|O_RDWR, 0666); > if (fd == -1) > -- > 2.17.1 >