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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 32B16C3524F for ; Mon, 3 Feb 2020 15:14:30 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D8F9122B48 for ; Mon, 3 Feb 2020 15:14:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="OGtzFIa+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D8F9122B48 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5ADB26B067C; Mon, 3 Feb 2020 10:14:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 556A96B067D; Mon, 3 Feb 2020 10:14:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3B0666B067E; Mon, 3 Feb 2020 10:14:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0195.hostedemail.com [216.40.44.195]) by kanga.kvack.org (Postfix) with ESMTP id 200F16B067C for ; Mon, 3 Feb 2020 10:14:29 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9297E181AEF1F for ; Mon, 3 Feb 2020 15:14:28 +0000 (UTC) X-FDA: 76449162216.02.size66_7e41c002ad93f X-HE-Tag: size66_7e41c002ad93f X-Filterd-Recvd-Size: 5201 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Mon, 3 Feb 2020 15:14:27 +0000 (UTC) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 48BBF846fMz9v3ls; Mon, 3 Feb 2020 16:14:20 +0100 (CET) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=OGtzFIa+; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 5VszB6UW2Yif; Mon, 3 Feb 2020 16:14:20 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 48BBF82h8pz9v3lm; Mon, 3 Feb 2020 16:14:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1580742860; bh=i4hAG7YwdO6LNDmYZ4wBEtikutj9N76WG5xl/PwnPrw=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=OGtzFIa+5ZhSxgd/BuHky5Jny2LDfnoF42zPtabwjmhorMsQSP8od+tqTvY9oMk3O ug6+KKaiRNlh/wtS69Y4UVsFdUJC1Vu36ZVhY++cHIlyr4PBVDhCfDbWqmvxtfLxhX pBTvZSaYZbiw2B0JwaU6kwU/pCLUp2ai2uhwAOdA= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 7DE228B7B0; Mon, 3 Feb 2020 16:14:25 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id unrhNEULKrXy; Mon, 3 Feb 2020 16:14:25 +0100 (CET) Received: from [172.25.230.102] (po15451.idsi0.si.c-s.fr [172.25.230.102]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 12E638B7AC; Mon, 3 Feb 2020 16:14:25 +0100 (CET) Subject: Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers To: Qian Cai Cc: Anshuman Khandual , linux-mm@kvack.org, Andrew Morton , Vlastimil Babka , Greg Kroah-Hartman , Thomas Gleixner , Mike Rapoport , Jason Gunthorpe , Dan Williams , Peter Zijlstra , Michal Hocko , Mark Rutland , Mark Brown , Steven Price , Ard Biesheuvel , Masahiro Yamada , Kees Cook , Tetsuo Handa , Matthew Wilcox , Sri Krishna chowdary , Dave Hansen , Russell King - ARM Linux , Michael Ellerman , Paul Mackerras , Martin Schwidefsky , Heiko Carstens , "David S. Miller" , Vineet Gupta , James Hogan , Paul Burton , Ralf Baechle , "Kirill A . Shutemov" , Gerald Schaefer , Ingo Molnar , linux-snps-arc@lists.infradead.org, linux-mips@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, kasan-dev References: <473d8198-3ac4-af3b-e2ec-c0698a3565d3@c-s.fr> <2C4ADFAE-7BB4-42B7-8F54-F036EA7A4316@lca.pw> From: Christophe Leroy Message-ID: <8e94a073-4045-89aa-6a3b-24847ad7c858@c-s.fr> Date: Mon, 3 Feb 2020 16:14:24 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <2C4ADFAE-7BB4-42B7-8F54-F036EA7A4316@lca.pw> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: quoted-printable 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: Le 02/02/2020 =C3=A0 12:26, Qian Cai a =C3=A9crit=C2=A0: >=20 >=20 >> On Jan 30, 2020, at 9:13 AM, Christophe Leroy wrote: >> >> config DEBUG_VM_PGTABLE >> bool "Debug arch page table for semantics compliance" if ARCH_HAS_= DEBUG_VM_PGTABLE || EXPERT >> depends on MMU >> default 'n' if !ARCH_HAS_DEBUG_VM_PGTABLE >> default 'y' if DEBUG_VM >=20 > Does it really necessary to potentially force all bots to run this? Syz= bot, kernel test robot etc? Does it ever pay off for all their machine ti= mes there? >=20 Machine time ? On a 32 bits powerpc running at 132 MHz, the tests takes less than 10ms.=20 Is it worth taking the risk of not detecting faults by not selecting it=20 by default ? [ 5.656916] debug_vm_pgtable: debug_vm_pgtable: Validating=20 architecture page table helpers [ 5.665661] debug_vm_pgtable: debug_vm_pgtable: Validated=20 architecture page table helpers Christophe