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[217.140.110.172]) by mx.google.com with ESMTP id x34si12562350edm.138.2019.07.25.21.28.24 for ; Thu, 25 Jul 2019 21:28:24 -0700 (PDT) Received-SPF: pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) client-ip=217.140.110.172; Authentication-Results: mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D942A337; Thu, 25 Jul 2019 21:28:23 -0700 (PDT) Received: from [10.163.1.197] (unknown [10.163.1.197]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 387953F694; Thu, 25 Jul 2019 21:28:18 -0700 (PDT) From: Anshuman Khandual Subject: Re: [RFC] mm/pgtable/debug: Add test validating architecture page table helpers To: Catalin Marinas Cc: linux-mm@kvack.org, Mark Rutland , x86@kernel.org, Kees Cook , Sri Krishna chowdary , Tetsuo Handa , Ard Biesheuvel , Dave Hansen , linux-kernel@vger.kernel.org, Matthew Wilcox , Michal Hocko , Masahiro Yamada , Mark Brown , Andrew Morton , Steven Price , linux-arm-kernel@lists.infradead.org References: <1564037723-26676-1-git-send-email-anshuman.khandual@arm.com> <1564037723-26676-2-git-send-email-anshuman.khandual@arm.com> <20190725170720.GB11545@arrakis.emea.arm.com> Message-ID: <066e69dc-6ecc-6aba-0226-ba1d61ca0fa8@arm.com> Date: Fri, 26 Jul 2019 09:58:56 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190725170720.GB11545@arrakis.emea.arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 07/25/2019 10:37 PM, Catalin Marinas wrote: > On Thu, Jul 25, 2019 at 12:25:23PM +0530, Anshuman Khandual wrote: >> +#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(__ARCH_HAS_4LEVEL_HACK) >> +static void pud_clear_tests(void) >> +{ >> + pud_t pud; >> + >> + pud_clear(&pud); >> + WARN_ON(!pud_none(pud)); >> +} > > For the clear tests, I think you should initialise the local variable to > something non-zero rather than rely on whatever was on the stack. In > case it fails, you have a more deterministic behaviour. Sure, it makes sense, will change.