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=-14.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham 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 870B6C432C0 for ; Fri, 29 Nov 2019 15:09:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3F914216F4 for ; Fri, 29 Nov 2019 15:09:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="oBgTgODv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F914216F4 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 E5CCD6B059B; Fri, 29 Nov 2019 10:09:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E0CB16B059C; Fri, 29 Nov 2019 10:09:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D23376B059E; Fri, 29 Nov 2019 10:09:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0245.hostedemail.com [216.40.44.245]) by kanga.kvack.org (Postfix) with ESMTP id BE3926B059B for ; Fri, 29 Nov 2019 10:09:09 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 89E52824D1B0 for ; Fri, 29 Nov 2019 15:09:09 +0000 (UTC) X-FDA: 76209648018.08.books19_15a1c72584a57 X-HE-Tag: books19_15a1c72584a57 X-Filterd-Recvd-Size: 6004 Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 29 Nov 2019 15:09:08 +0000 (UTC) Received: by mail-pf1-f194.google.com with SMTP id s18so6178661pfd.8 for ; Fri, 29 Nov 2019 07:09:08 -0800 (PST) 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=PkXm5Uh6VdJR1UhdG1t5DvbTDpOG78WxFWvkUivLCK4=; b=oBgTgODvOxw19aKa0yD+J2olPiukXrUgSW0xcudI+2Nx1BGE43Fh9HSlCNnyOdY5T7 PVDJ6RKqVHrn5F8Zeb0yRyEyn4JMGEMLgO6JypIQO5EzcYkumQn1pLIB1kzsNiM5YSir dtl5hD/s5o0CF5Xv5GIyNrZAPva7rQjHUnTCmg7p3TCDaVjyFGueRCXrffDDSn048C4u tOO/HBIYQntFhLltXkCn5KtGIg6cwhJV9pjDWIwtP6BG65HZWVBUjmCvQ1sGmzFAZ40J IiBj75TDu2flNq8+2pI96Bg1CCGT/KIa1C+of4rD2mE1nhrOZgBSrrjDy8htLoi752us gEww== 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=PkXm5Uh6VdJR1UhdG1t5DvbTDpOG78WxFWvkUivLCK4=; b=ldilNOhXmO8bbLVO6x57AJIUfIY3I62DFFpI4EiKUHuN7cL+m/JA/hQx8zc+fYCyqQ rGsxJ106JeqsgNZUhfJmyMVNHBVq+ZzEjDdFEZCyYVvMTf0Yc1/KKbKxmoRJVAEkmLQo zSPq0wpb4H4q7hBQUyU7HvJjkj3BTxCvC/gu5BKXIOil8BNSwJEiPpdfQPVODd+5XjwB 0117n7g01T4jYw9iMtFHxaK0p9dkHfWVt32G8+/dqVUnHkkv7J4eW0q34dJcYi+81OH3 23gtJGNZYLe93QSHmHqiB0RAi0QxKXl6Fx3Bashd1av+7V+SXpJVPsQ79XW0+ez5v/KZ TW5Q== X-Gm-Message-State: APjAAAVpGs+TUxqHNzYaj6jNJc3SOyqfrIx7WZZjmPwXUQu3ima8J5JN C+xdpLuDTldMWCz22cnqcCVpscohl6F5vLcDM0oYtA== X-Google-Smtp-Source: APXvYqzZjdWrDa5OTpgFC4whG5dZUZ0qoqa/GKrLqj9cv/3LGKKgplSSrAl4mP9cs2LAZv+4TdaepUE5VQrcDWRcZas= X-Received: by 2002:a63:31d0:: with SMTP id x199mr17700498pgx.286.1575040147329; Fri, 29 Nov 2019 07:09:07 -0800 (PST) MIME-Version: 1.0 References: <20191122112621.204798-1-glider@google.com> <20191122112621.204798-26-glider@google.com> In-Reply-To: <20191122112621.204798-26-glider@google.com> From: Andrey Konovalov Date: Fri, 29 Nov 2019 16:08:56 +0100 Message-ID: Subject: Re: [PATCH RFC v3 25/36] kmsan: unpoison |tlb| in arch_tlb_gather_mmu() To: Alexander Potapenko Cc: Vegard Nossum , Dmitry Vyukov , Linux Memory Management List , Alexander Viro , Andreas Dilger , Andrew Morton , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , darrick.wong@oracle.com, "David S. Miller" , Dmitry Torokhov , Eric Biggers , Eric Dumazet , ericvh@gmail.com, Greg Kroah-Hartman , harry.wentland@amd.com, Herbert Xu , iii@linux.ibm.com, mingo@elte.hu, Jason Wang , Jens Axboe , Marek Szyprowski , Marco Elver , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S . Tsirkin" , Michal Simek , pmladek@suse.com, Qian Cai , Randy Dunlap , Robin Murphy , sergey.senozhatsky@gmail.com, Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Thomas Gleixner , gor@linux.ibm.com, wsa@the-dreams.de 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: Archived-At: List-Archive: List-Post: On Fri, Nov 22, 2019 at 12:27 PM wrote: > > This is a hack to reduce stackdepot pressure. I think this patch needs a better description :) Like in the comment below. > > Signed-off-by: Alexander Potapenko > To: Alexander Potapenko > Cc: Vegard Nossum > Cc: Dmitry Vyukov > Cc: linux-mm@kvack.org > > --- > > Change-Id: I22a201e7e4f67ed74f8129072f12e5351b26103a > --- > mm/mmu_gather.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c > index 7d70e5c78f97..8c5ea2d2e7d5 100644 > --- a/mm/mmu_gather.c > +++ b/mm/mmu_gather.c > @@ -1,6 +1,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -206,6 +207,15 @@ void tlb_flush_mmu(struct mmu_gather *tlb) > void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, > unsigned long start, unsigned long end) > { > + /* > + * TODO(glider): struct mmu_gather contains 7 1-bit fields packed into a Remove TODO? > + * 32-bit unsigned int value. The remaining 25 bits remain uninitialized > + * and are never used, but KMSAN updates the origin for them in > + * zap_pXX_range() in mm/memory.c, thus creating very long origin > + * chains. This is technically correct, but consumes too much memory. > + * Unpoisoning the whole structure will prevent creating such chains. > + */ > + kmsan_unpoison_shadow(tlb, sizeof(*tlb)); > tlb->mm = mm; > > /* Is it from 0 to ~0? */ > -- > 2.24.0.432.g9d3f5f5b63-goog >