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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 54B55C432C2 for ; Wed, 25 Sep 2019 19:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26BAB21D7B for ; Wed, 25 Sep 2019 19:59:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WPW9NjK8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392625AbfIYT7i (ORCPT ); Wed, 25 Sep 2019 15:59:38 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:47323 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728589AbfIYT7h (ORCPT ); Wed, 25 Sep 2019 15:59:37 -0400 Received: by mail-pf1-f201.google.com with SMTP id t65so4663585pfd.14 for ; Wed, 25 Sep 2019 12:59:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=nSSSsCHQoO5MrGz/qVzfoHlRr3sXZuE5W1f65hgD98s=; b=WPW9NjK89aM5m4GLnGHjzhxbX08OMgdZp31NaUOc1Vash/wJDS9R31U+Xb9tczJkXP p5WarRaQoX9OT3q7FBAHAC5j6gSc8hvrH+oEr7ok/LqoXrsNuDdwyKDxZXC6o9uE9B/q FA2H6pzp2cisAaZh5OW1hB+COt/+6xQT9Nukki06GfCicFAKSmb2b99eZAkt7PNH3ldu V/rieCtpzwLQp+l+JJbTPjyy1/dRetdxj4PpAw1Ls3rKBwbmadZ4ygyPNT8+W3SnwUHv mCj9d7nTkZPLi3LR/FlOQl6Gk4WSJe3Ds2vsnVjH0/7y4dP1gKkMG8qp1or+UIwpcfoa upvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=nSSSsCHQoO5MrGz/qVzfoHlRr3sXZuE5W1f65hgD98s=; b=CqrZY2Yz6a7x6aCz9KPX2kA2kbFAOt60ADyTuOxNPofC0U4KhrBuQsJ6I7QE1ftjTU rUA8LHRbsnwgO/goRztnwGJQgq90P3j5hfD8Ui0Pxc1xBofTLz1GTg6x6wcguEaurF/W 5yn4Smj/YfHNFHZ97t/BiFYNvFij02MVyNz2x17NDSk1RWDMRuKErZezdFO9lrmkVsEZ Z33PsqJb/TbJ/JhbLoRQ0i3dWzNH3StniQRXkmYqEcvtdnssFBVrV371f6zZkWtWiv+e 1U9NbzC6IgoGIFjqjcINhS6LyagoUPReuDbhvn7bUh7sP8NjYJaKrMawkL8O54WNQAv/ XNRg== X-Gm-Message-State: APjAAAUFaI8nnqLJP7Vwb0gfXBNjkW4Yv7lXGNEJm28zKvCHLfs3ibif 3wUJ/BZCeQqVSewhVVHgfXOB84KTWGA5 X-Google-Smtp-Source: APXvYqzm76+RK5PwLaNfUmf7msNP0MHZo0N5d0IA9KndyRPIrHeIUPaFs8N1kYJo+yjbZozv46+2Vos0zZX5 X-Received: by 2002:a63:e511:: with SMTP id r17mr1115476pgh.374.1569441576756; Wed, 25 Sep 2019 12:59:36 -0700 (PDT) Date: Wed, 25 Sep 2019 12:59:24 -0700 In-Reply-To: <20190925195924.152834-1-irogers@google.com> Message-Id: <20190925195924.152834-2-irogers@google.com> Mime-Version: 1.0 References: <20190925195924.152834-1-irogers@google.com> X-Mailer: git-send-email 2.23.0.351.gc4317032e6-goog Subject: [PATCH 2/2] Avoid raising segv using an obvious null dereference From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , linux-kernel@vger.kernel.org Cc: Stephane Eranian , Ian Rogers Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Ian Rogers --- 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 dbc27199c65e..dd865e0bea12 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) -- 2.23.0.351.gc4317032e6-goog