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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 A8D3DC2D0E5 for ; Wed, 25 Mar 2020 18:03:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5330F20774 for ; Wed, 25 Mar 2020 18:03:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ksrmWoK2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5330F20774 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D94126B00C4; Wed, 25 Mar 2020 14:03:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D448B6B00C5; Wed, 25 Mar 2020 14:03:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C34656B00C6; Wed, 25 Mar 2020 14:03:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0210.hostedemail.com [216.40.44.210]) by kanga.kvack.org (Postfix) with ESMTP id AB5F86B00C4 for ; Wed, 25 Mar 2020 14:03:47 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 828888248047 for ; Wed, 25 Mar 2020 18:03:47 +0000 (UTC) X-FDA: 76634657694.30.top96_3e1bea37c6a37 X-HE-Tag: top96_3e1bea37c6a37 X-Filterd-Recvd-Size: 4955 Received: from mail-wm1-f67.google.com (mail-wm1-f67.google.com [209.85.128.67]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Wed, 25 Mar 2020 18:03:46 +0000 (UTC) Received: by mail-wm1-f67.google.com with SMTP id z5so3516450wml.5 for ; Wed, 25 Mar 2020 11:03:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=URS76Zy/AQ63zV06wZwyTsZw846bsas30Ld2m7ty/aU=; b=ksrmWoK2Qqe4bswmKsUUPqiC2/HrY2JOFy8MCQJcCl/UK1q3IjkXKk8UR/qB3AMFGA oSdh8C6QXM/KPeEZw89Hodhpe7Q0d8YXjYW4n6jA9fr6v9UOQRx6Ic4Jw+LrIcIBrUcj FgCSlE1XW9ZuZVHDRFihrL/jYubUYICnByru9ACPsGCvZOpzy8hsl9LKZ2QQm0pW2Uuj TaiVIx2vVjWlcGOJQVL+m792uepexLOhYMlZegEnO0y2KGFHY9Z65qrYqgGLfng29KPX WofUPMrgStKgKEvgI/lgqlFIp/EslIysYcMjQqFnQ0qZ5Fe5z3cwWdmxItfjy+D1xpsM 5I4Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=URS76Zy/AQ63zV06wZwyTsZw846bsas30Ld2m7ty/aU=; b=nomstrpCU8FYzvR4iZoW0tcXPCyTGIXct0kYeH4Z32bM11J7AGGlyw/Oba8K9gshD2 Ximp+l8/wzcGbIOhoEROP9GUb6Zc/cKo+3C2amgF07dcfOZof8sf1oOscoU622h3tpLk Pe1PuFXmdTwmva7TrBCbPfyWCmmUCTpQ/cCicdHMLW7s3BOCIZwptJQ1yo1L3aOU80pz I3MBoA+i2HAG3MuVqvcp615DljfbH1zEIAMM312ClkalkW8FXpJ6e+Ah2gP3ALQR9vrA zKBNUB0Xos/n3YCcDh6LDJao0syASZcYOcgl6AU5spVt+vgmb3CXKS8LKa7OVFkQXSvB Tzeg== X-Gm-Message-State: ANhLgQ3SCWj4FCWAFYn3vc3rzrUgNm3+JF/6E/hqAPvmdJHVWPDS9QZq CnM81g730vr6K6vLozlqFSTWb/B1KbbqwYUzcUPWEg== X-Google-Smtp-Source: ADFU+vufIxtejQ+StJKncl0J8FogKdz6vZd6GKYo5zS4R4R9HTgctj3HEsGrbvh6dzxaFV5Et0J8VyKCMJZV0snNivw= X-Received: by 2002:a1c:ed1a:: with SMTP id l26mr4562254wmh.175.1585159424305; Wed, 25 Mar 2020 11:03:44 -0700 (PDT) MIME-Version: 1.0 References: <20200325161249.55095-1-glider@google.com> <20200325161249.55095-4-glider@google.com> <20200325161952.GF19542@dhcp22.suse.cz> <20200325174916.GC22483@bombadil.infradead.org> In-Reply-To: <20200325174916.GC22483@bombadil.infradead.org> From: Alexander Potapenko Date: Wed, 25 Mar 2020 19:03:32 +0100 Message-ID: Subject: Re: [PATCH v5 03/38] kmsan: gfp: introduce __GFP_NO_KMSAN_SHADOW To: Matthew Wilcox Cc: Michal Hocko , Vegard Nossum , Andrew Morton , Dmitry Vyukov , Marco Elver , Andrey Konovalov , Linux Memory Management List , Al Viro , Andreas Dilger , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , David Miller , Dmitry Torokhov , Eric Biggers , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Mark Rutland , "Martin K . Petersen" , Martin Schwidefsky , "Michael S. Tsirkin" , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Thomas Gleixner , Vasily Gorbik , Wolfram Sang Content-Type: text/plain; charset="UTF-8" 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: > I would suggest using bits in the section labelled: > > /* Unserialized, strictly 'current' */ The main problem is that |current| is unavailable in the interrupt context, so we'll also need to: - disable interrupts when preparing for a KMSAN internal memory allocation - sounds costly, huh? - store the context flag in a per-cpu variable in the case |current| is unavailable.