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=-10.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 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 6DB91C4363C for ; Wed, 7 Oct 2020 18:20:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0887A2173E for ; Wed, 7 Oct 2020 18:20:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="VNKeTK7z" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727688AbgJGSU4 (ORCPT ); Wed, 7 Oct 2020 14:20:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39618 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726100AbgJGSU4 (ORCPT ); Wed, 7 Oct 2020 14:20:56 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5224DC061755 for ; Wed, 7 Oct 2020 11:20:56 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id d6so1399578plo.13 for ; Wed, 07 Oct 2020 11:20:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=5q1mkem07H8Ft+Xbkac3QH7U1U4PTRmUXcm4ZQ/v9FM=; b=VNKeTK7zHJF6+X2eOrSRKIuojJ63hohCmMz/vlj6m1JcBFxP+dLAZ10vxL8rZCHAJQ Tiac7HW3AFZUU5J8s4UsZm5IvqQnuniESW6saHdxaUukh73KOok+xuY3I9Twcvv9Hsnn ZSX51TqQs4hphqfPuY4zgoKbbR+KMVnVnPuAw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=5q1mkem07H8Ft+Xbkac3QH7U1U4PTRmUXcm4ZQ/v9FM=; b=gMVcuSjRJc5Qhzz5iqCWwMGK6EaoCKvWlpqJMCXHXufvNkcaaUxSCQKh+whjFPw5bg 1dqQoAs3E9mSg9mKITIuTRP3Qd+aPsWmqxUdD/NwCG3MqYPT+91Hz3BNCVvKeFF44C5j qy4Cfs7A7qikQsce0Puye11YXQTTk9QMAbFmfKqjlmzGIHsELxogZ/NmBu5696ESv/kr m6E+1fyTBMbKkKJdJaZAvQ8/fXX2QBfJn4VpiUEIzaIPSsTGhORvRS3GxdwiDP9hP1BS WiEGMb994En9Tgv8FNDQk3AA2wWhY0azlnOSwPmogzQJE6CJQG8SLGoyyN0q03AHdrVs aEsA== X-Gm-Message-State: AOAM532dC1zBkWcuOX8SsCLNzTAofZiaDFZCKXKkn2CtIOLmJaNVcxLB I/5sNVwiBLULr++EbKZIUR8Dmw== X-Google-Smtp-Source: ABdhPJytI8S0ylF92xO+QtqqcxVb2t5ate4wepbxVrTBVldSJYIFpg4BxOAMRISqnSvwQ/D93qRpyg== X-Received: by 2002:a17:902:7896:b029:d3:7768:1eb with SMTP id q22-20020a1709027896b02900d3776801ebmr4033216pll.17.1602094855805; Wed, 07 Oct 2020 11:20:55 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id s67sm4034679pfb.35.2020.10.07.11.20.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2020 11:20:54 -0700 (PDT) Date: Wed, 7 Oct 2020 11:20:53 -0700 From: Kees Cook To: Shuah Khan Cc: gregkh@linuxfoundation.org, rafael@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 08/11] drivers/base/test/test_async_driver_probe: convert to use counter_atomic32 Message-ID: <202010071119.0D23F28@keescook> References: <7a259f1710f621a95d6e683308e55bd74bba2a2f.1602011710.git.skhan@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7a259f1710f621a95d6e683308e55bd74bba2a2f.1602011710.git.skhan@linuxfoundation.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 06, 2020 at 02:44:39PM -0600, Shuah Khan wrote: > counter_atomic* is introduced to be used when a variable is used as > a simple counter and doesn't guard object lifetimes. This clearly > differentiates atomic_t usages that guard object lifetimes. > > counter_atomic* variables will wrap around to 0 when it overflows and > should not be used to guard resource lifetimes, device usage and > open counts that control state changes, and pm states. > > atomic_t variables used to count errors, warns, keep track of timeout, > and async completion are counters. > > Unsure overflow is a concern for timeout and async completion, and there > are no checks for overflow to hold them to upper bounds. Overflow and > wrap around doesn't impact errors, and warns. > > Convert them to use counter_atomic32. > > This conversion doesn't change the overflow wrap around behavior. > > Reviewed-by: Greg Kroah-Hartman > Signed-off-by: Shuah Khan > --- > drivers/base/test/test_async_driver_probe.c | 23 ++++++++++++--------- > 1 file changed, 13 insertions(+), 10 deletions(-) > > diff --git a/drivers/base/test/test_async_driver_probe.c b/drivers/base/test/test_async_driver_probe.c > index 3bb7beb127a9..e969c1b09426 100644 > --- a/drivers/base/test/test_async_driver_probe.c > +++ b/drivers/base/test/test_async_driver_probe.c > @@ -14,11 +14,12 @@ > #include > #include > #include > +#include > > #define TEST_PROBE_DELAY (5 * 1000) /* 5 sec */ > #define TEST_PROBE_THRESHOLD (TEST_PROBE_DELAY / 2) > > -static atomic_t warnings, errors, timeout, async_completed; > +static struct counter_atomic32 warnings, errors, timeout, async_completed; While it's currently harmless, this should likely be using COUNTER_ATOMIC_INIT(0)s... > > static int test_probe(struct platform_device *pdev) > { > @@ -29,9 +30,9 @@ static int test_probe(struct platform_device *pdev) > * have then report it as an error, otherwise we wil sleep for the > * required amount of time and then report completion. > */ > - if (atomic_read(&timeout)) { > + if (counter_atomic32_read(&timeout)) { > dev_err(dev, "async probe took too long\n"); > - atomic_inc(&errors); > + counter_atomic32_inc(&errors); > } else { > dev_dbg(&pdev->dev, "sleeping for %d msecs in probe\n", > TEST_PROBE_DELAY); > @@ -48,10 +49,10 @@ static int test_probe(struct platform_device *pdev) > dev_to_node(dev) != numa_node_id()) { > dev_warn(dev, "NUMA node mismatch %d != %d\n", > dev_to_node(dev), numa_node_id()); > - atomic_inc(&warnings); > + counter_atomic32_inc(&warnings); > } > > - atomic_inc(&async_completed); > + counter_atomic32_inc(&async_completed); > } > > return 0; > @@ -244,11 +245,12 @@ static int __init test_async_probe_init(void) > * Otherwise if they completed without errors or warnings then > * report successful completion. > */ > - if (atomic_read(&async_completed) != async_id) { > + if (counter_atomic32_read(&async_completed) != async_id) { > pr_err("async events still pending, forcing timeout\n"); > - atomic_inc(&timeout); > + counter_atomic32_inc(&timeout); > err = -ETIMEDOUT; > - } else if (!atomic_read(&errors) && !atomic_read(&warnings)) { > + } else if (!counter_atomic32_read(&errors) && > + !counter_atomic32_read(&warnings)) { > pr_info("completed successfully\n"); > return 0; > } > @@ -271,12 +273,13 @@ static int __init test_async_probe_init(void) > * errors or warnings being reported by the probe routine. > */ > if (err) > - atomic_inc(&errors); > + counter_atomic32_inc(&errors); > else > err = -EINVAL; > > pr_err("Test failed with %d errors and %d warnings\n", > - atomic_read(&errors), atomic_read(&warnings)); > + counter_atomic32_read(&errors), > + counter_atomic32_read(&warnings)); > > return err; > } > -- > 2.25.1 > But yeah, this is otherwise just reporting and simple one-time synchronization. Reviewed-by: Kees Cook -- Kees Cook