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Date:   Thu, 25 Jul 2019 18:07:21 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Anshuman Khandual <anshuman.khandual@arm.com>
Cc:     linux-mm@kvack.org, Mark Rutland <mark.rutland@arm.com>,
        x86@kernel.org, Kees Cook <keescook@chromium.org>,
        Sri Krishna chowdary <schowdary@nvidia.com>,
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        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Dave Hansen <dave.hansen@intel.com>,
        linux-kernel@vger.kernel.org, Matthew Wilcox <willy@infradead.org>,
        Michal Hocko <mhocko@kernel.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Mark Brown <Mark.Brown@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Steven Price <Steven.Price@arm.com>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC] mm/pgtable/debug: Add test validating architecture page
 table helpers
Message-ID: <20190725170720.GB11545@arrakis.emea.arm.com>
References: <1564037723-26676-1-git-send-email-anshuman.khandual@arm.com>
 <1564037723-26676-2-git-send-email-anshuman.khandual@arm.com>
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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.

-- 
Catalin