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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 7CD31C433F5 for ; Tue, 21 Sep 2021 16:33:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64C926023D for ; Tue, 21 Sep 2021 16:33:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229705AbhIUQfE (ORCPT ); Tue, 21 Sep 2021 12:35:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229679AbhIUQfA (ORCPT ); Tue, 21 Sep 2021 12:35:00 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 19673C061574 for ; Tue, 21 Sep 2021 09:33:32 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id z8-20020a056214040800b00380dea65c01so24912862qvx.4 for ; Tue, 21 Sep 2021 09:33:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=XXlfpcBmbRno5SA+gst6Gevlk7ltg9389UQ9dhNVCvA=; b=Wf+QnXwZGfTR93ea68ZPKzFik9oK5cF0gl/6r7BXDTKkCEkNlT5puLNHR76CLQ4TxS sqnivS0sK15CMFeU/ykdAnnhQlLBTCOEwfM3X+Sc1uvAZ3q2dU+XX2CTC6tqtw/qpobw jEpk3zQXOidiuHrp/6oAP/MWm+Ybq220aML/CuZnSDiuYveXKux6S17aaiLnikWbL+QL k+qzoGVvrmTGw0A2trsphU4lw0U4aTCe3vkkP2ZuPFRvH5Eg6dTZcXR2p3I8D0o3GQAN wmv53dN1fi7EhnyFpRlW+rbaFzAB2o8DOg/NIAJK4uDK/coDPCIvKWAdo9GuKq7tFxG7 uVsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=XXlfpcBmbRno5SA+gst6Gevlk7ltg9389UQ9dhNVCvA=; b=eWxFVB1hk6NgDXygu8TK1z8CwBbESc40jqJIEQFakQyat+qf7TVPrtoUWd7BBA7TaO Jb+GOd9qMf/ScYwH34jahZ2wOjJGs4J2MJGmAz5hqgWX2f/nccxLSiTQiuLMm8CLXs5k Rv8GiLavniwdQX/Vfh6FEL8H3r7ufhF99Gyf6j9FYTfere9c3udSAptcqtwzO/EJ2LWl RA3pDZR82lQrEcIhML1P7B3y7OFu3wjC/8bxQxtCoJPaeOZYlVp4saNOVddqb9xq7BeW ylRlauaB6uJlcKFxCt1LVHqza4l4ikJwHqv4WumrncXklsplBz8oZrxLCaEj8wZZNbmw Le3A== X-Gm-Message-State: AOAM5320GcfcwfBeZ7kEv97o9KGTK5AWRsK5qPYrhWcVNekN3cZ6Cd9e JEN3GWohUhmrPgA8I/g2K/KeUw28askvr6sbyVO+ X-Google-Smtp-Source: ABdhPJwgz8JIJfqh2iJ8cYLJJQmL1F5G7QJHu8shYN6bVP9STb44sPjeNHitaFyPqxCJcvfDRzpn0Hr1vzMSdjOiXvAJ X-Received: from ajr0.svl.corp.google.com ([2620:15c:2cd:203:ed57:a230:8c3d:64d8]) (user=axelrasmussen job=sendgmr) by 2002:a05:6902:124e:: with SMTP id t14mr39259664ybu.106.1632242011222; Tue, 21 Sep 2021 09:33:31 -0700 (PDT) Date: Tue, 21 Sep 2021 09:33:23 -0700 In-Reply-To: <20210921163323.944352-1-axelrasmussen@google.com> Message-Id: <20210921163323.944352-3-axelrasmussen@google.com> Mime-Version: 1.0 References: <20210921163323.944352-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.33.0.464.g1972c5931b-goog Subject: [PATCH 3/3] userfaultfd/selftests: don't rely on GNU extensions for random numbers From: Axel Rasmussen To: Andrew Morton , Peter Xu , Shuah Khan Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Axel Rasmussen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Two arguments for doing this: First, and maybe most importantly, the resulting code is significantly shorter / simpler. Then, we avoid using GNU libc extensions. Why does this matter? It makes testing userfaultfd with the selftest easier e.g. on distros which use something other than glibc (e.g., Alpine, which uses musl); basically, it makes the test more portable. Signed-off-by: Axel Rasmussen --- tools/testing/selftests/vm/userfaultfd.c | 26 ++++-------------------- 1 file changed, 4 insertions(+), 22 deletions(-) diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index aad5211f5012..9d9f60e71524 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -57,6 +57,7 @@ #include #include #include +#include #include "../kselftest.h" @@ -528,22 +529,10 @@ static void continue_range(int ufd, __u64 start, __u64 len) static void *locking_thread(void *arg) { unsigned long cpu = (unsigned long) arg; - struct random_data rand; unsigned long page_nr = *(&(page_nr)); /* uninitialized warning */ - int32_t rand_nr; unsigned long long count; - char randstate[64]; - unsigned int seed; - if (bounces & BOUNCE_RANDOM) { - seed = (unsigned int) time(NULL) - bounces; - if (!(bounces & BOUNCE_RACINGFAULTS)) - seed += cpu; - bzero(&rand, sizeof(rand)); - bzero(&randstate, sizeof(randstate)); - if (initstate_r(seed, randstate, sizeof(randstate), &rand)) - err("initstate_r failed"); - } else { + if (!(bounces & BOUNCE_RANDOM)) { page_nr = -bounces; if (!(bounces & BOUNCE_RACINGFAULTS)) page_nr += cpu * nr_pages_per_cpu; @@ -551,15 +540,8 @@ static void *locking_thread(void *arg) while (!finished) { if (bounces & BOUNCE_RANDOM) { - if (random_r(&rand, &rand_nr)) - err("random_r failed"); - page_nr = rand_nr; - if (sizeof(page_nr) > sizeof(rand_nr)) { - if (random_r(&rand, &rand_nr)) - err("random_r failed"); - page_nr |= (((unsigned long) rand_nr) << 16) << - 16; - } + if (getrandom(&page_nr, sizeof(page_nr), 0) != sizeof(page_nr)) + err("getrandom failed"); } else page_nr += 1; page_nr %= nr_pages; -- 2.33.0.464.g1972c5931b-goog