linux-kernel - Re: [RFC] mm/pgtable/debug: Add test validating architecture page table helpers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190725170720.GB11545@arrakis.emea.arm.com>
Date:   Thu, 25 Jul 2019 18:07:21 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-mm@...ck.org, Mark Rutland <mark.rutland@....com>,
        x86@...nel.org, Kees Cook <keescook@...omium.org>,
        Sri Krishna chowdary <schowdary@...dia.com>,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Dave Hansen <dave.hansen@...el.com>,
        linux-kernel@...r.kernel.org, Matthew Wilcox <willy@...radead.org>,
        Michal Hocko <mhocko@...nel.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Mark Brown <Mark.Brown@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Steven Price <Steven.Price@....com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC] mm/pgtable/debug: Add test validating architecture page
 table helpers

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