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 DD1CDCA9EC9 for ; Mon, 4 Nov 2019 22:15:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B216D204EC for ; Mon, 4 Nov 2019 22:15:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572905739; bh=sn9PuHWrsSWJy+qnRz1rl2QGZbrjTOyXUksthEqa3vc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SuHgMMpiJa5/kVEqWzUTcX+bGMhjNfxZrj/mOgtrU4XEWTgYC8qTgxGWxQK6xcSv5 rcIHUCF3s0YnCW8/7GnSKFUEKwLWeW4v1b8azw9eswdY5JQZ9oyIu3UiWdSLNYguIb 8sjLoh9vXv9S27Z2DMc2Wl+FegQ3IRAeZGhehDHc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390450AbfKDWPi (ORCPT ); Mon, 4 Nov 2019 17:15:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:37450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387876AbfKDWFw (ORCPT ); Mon, 4 Nov 2019 17:05:52 -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 3C50D2084D; Mon, 4 Nov 2019 22:05:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572905152; bh=sn9PuHWrsSWJy+qnRz1rl2QGZbrjTOyXUksthEqa3vc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wLW8TSf+uAZEjqvklYSIGKsb/U2KOqvGO4pBcGj6GSgbK9zkySExP0fi52t13mJgC wT5FRoYHLQUiBMGl/qvX7iAeVW+GTeyQ5ABYNneDNsqDDoDLwGtVcoPQorwFMy4Xd3 C7TT6zns1U8drKgKYpiiy280MUuh4G3Fcsk5fSb4= 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 5.3 009/163] perf tests: Avoid raising SEGV using an obvious NULL dereference Date: Mon, 4 Nov 2019 22:43:19 +0100 Message-Id: <20191104212141.185441579@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191104212140.046021995@linuxfoundation.org> References: <20191104212140.046021995@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