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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 83BDCCA9EC9 for ; Mon, 4 Nov 2019 21:59:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5806E217F4 for ; Mon, 4 Nov 2019 21:59:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572904772; bh=sn9PuHWrsSWJy+qnRz1rl2QGZbrjTOyXUksthEqa3vc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=grPI5ojVITrgqhqy2g4QvXXRmDM+kvSeHIIPFTKO4EUewcSqAvwHeOfLmAw7ow9qG AsBhye76lmfRj+UowU9ZNpkANox59RHqZfIyaBVKbdSZZL7Oc0LIkcByD5mHoTOnpW jLVr9+4VmKGr7+SLij/1ezkT8SjI89seFQGfP6ms= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388218AbfKDV7b (ORCPT ); Mon, 4 Nov 2019 16:59:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:56516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387847AbfKDV7W (ORCPT ); Mon, 4 Nov 2019 16:59:22 -0500 Received: from localhost (6.204-14-84.ripe.coltfrance.com [84.14.204.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8742920650; Mon, 4 Nov 2019 21:59:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572904762; bh=sn9PuHWrsSWJy+qnRz1rl2QGZbrjTOyXUksthEqa3vc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OmNmHspbpceKtlJniIKP2k/9wHh7JkcVnft+t09rRysK6u1fGzQWZuefAQ1X0UCYw 7lpl5QECHeNAUi+RGPgDMYZa0e3enbURdHWHQsvCDNGgK41pbFlrNyvclefbsxpXbb t/cpGmwjGdGbImgIrQo3ZiWcd4ZbfBEGVb0ESA5Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ian Rogers , Arnaldo Carvalho de Melo , Alexander Shishkin , Andi Kleen , Jiri Olsa , Namhyung Kim , Peter Zijlstra , Stephane Eranian , Wang Nan , Sasha Levin Subject: [PATCH 4.19 061/149] perf tests: Avoid raising SEGV using an obvious NULL dereference Date: Mon, 4 Nov 2019 22:44:14 +0100 Message-Id: <20191104212141.041151631@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191104212126.090054740@linuxfoundation.org> References: <20191104212126.090054740@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Rogers [ Upstream commit e3e2cf3d5b1fe800b032e14c0fdcd9a6fb20cf3b ] 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 Signed-off-by: Sasha Levin --- 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 a693bcf017ea2..44c16fd11bf6e 100644 --- a/tools/perf/tests/perf-hooks.c +++ b/tools/perf/tests/perf-hooks.c @@ -20,12 +20,11 @@ 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) -- 2.20.1