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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 EF560ECE58C for ; Mon, 7 Oct 2019 14:50:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D08C221479 for ; Mon, 7 Oct 2019 14:50:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728376AbfJGOtq (ORCPT ); Mon, 7 Oct 2019 10:49:46 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:44472 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728588AbfJGOtk (ORCPT ); Mon, 7 Oct 2019 10:49:40 -0400 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1iHUKF-00065n-5e; Mon, 07 Oct 2019 16:49:27 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id E70521C08B0; Mon, 7 Oct 2019 16:49:17 +0200 (CEST) Date: Mon, 07 Oct 2019 14:49:17 -0000 From: "tip-bot2 for Ian Rogers" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: perf/urgent] perf tests: Avoid raising SEGV using an obvious NULL dereference Cc: Ian Rogers , Arnaldo Carvalho de Melo , Alexander Shishkin , Andi Kleen , Jiri Olsa , Namhyung Kim , Peter Zijlstra , Stephane Eranian , Wang Nan , Ingo Molnar , Borislav Petkov , linux-kernel@vger.kernel.org In-Reply-To: <20190925195924.152834-2-irogers@google.com> References: <20190925195924.152834-2-irogers@google.com> MIME-Version: 1.0 Message-ID: <157045975781.9978.17507056715784418883.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the perf/urgent branch of tip: Commit-ID: e3e2cf3d5b1fe800b032e14c0fdcd9a6fb20cf3b Gitweb: https://git.kernel.org/tip/e3e2cf3d5b1fe800b032e14c0fdcd9a6fb20cf3b Author: Ian Rogers AuthorDate: Wed, 25 Sep 2019 12:59:24 -07:00 Committer: Arnaldo Carvalho de Melo CommitterDate: Fri, 27 Sep 2019 09:26:14 -03:00 perf tests: Avoid raising SEGV using an obvious NULL dereference An optimized build such as: make -C tools/perf CLANG=1 CC=clang EXTRA_CFLAGS="-O3 will turn the dereference operation into a ud2 instruction, raising a SIGILL rather than a SIGSEGV. Use raise(..) for correctness and clarity. Similar issues were addressed in Numfor Mbiziwo-Tiapo's patch: https://lkml.org/lkml/2019/7/8/1234 Committer testing: Before: [root@quaco ~]# perf test hooks 55: perf hooks : Ok [root@quaco ~]# perf test -v hooks 55: perf hooks : --- start --- test child forked, pid 17092 SIGSEGV is observed as expected, try to recover. Fatal error (SEGFAULT) in perf hook 'test' test child finished with 0 ---- end ---- perf hooks: Ok [root@quaco ~]# After: [root@quaco ~]# perf test hooks 55: perf hooks : Ok [root@quaco ~]# perf test -v hooks 55: perf hooks : --- start --- test child forked, pid 17909 SIGSEGV is observed as expected, try to recover. Fatal error (SEGFAULT) in perf hook 'test' test child finished with 0 ---- end ---- perf hooks: Ok [root@quaco ~]# Fixes: a074865e60ed ("perf tools: Introduce perf hooks") Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Wang Nan Link: http://lore.kernel.org/lkml/20190925195924.152834-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/tests/perf-hooks.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/tools/perf/tests/perf-hooks.c b/tools/perf/tests/perf-hooks.c index dbc2719..dd865e0 100644 --- a/tools/perf/tests/perf-hooks.c +++ b/tools/perf/tests/perf-hooks.c @@ -19,12 +19,11 @@ static void sigsegv_handler(int sig __maybe_unused) static void the_hook(void *_hook_flags) { int *hook_flags = _hook_flags; - int *p = NULL; *hook_flags = 1234; /* Generate a segfault, test perf_hooks__recover */ - *p = 0; + raise(SIGSEGV); } int test__perf_hooks(struct test *test __maybe_unused, int subtest __maybe_unused)