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=-11.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, 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 78F0CC282DD for ; Wed, 8 Jan 2020 16:14:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 37F99206F0 for ; Wed, 8 Jan 2020 16:14:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="enM6XWMD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 37F99206F0 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 AFC468E0005; Wed, 8 Jan 2020 11:14:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AAB3A8E0001; Wed, 8 Jan 2020 11:14:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 99A278E0005; Wed, 8 Jan 2020 11:14:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0086.hostedemail.com [216.40.44.86]) by kanga.kvack.org (Postfix) with ESMTP id 814DC8E0001 for ; Wed, 8 Jan 2020 11:14:19 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 22F948249980 for ; Wed, 8 Jan 2020 16:14:19 +0000 (UTC) X-FDA: 76354964238.22.arch62_8855d8bfb127 X-HE-Tag: arch62_8855d8bfb127 X-Filterd-Recvd-Size: 5583 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Wed, 8 Jan 2020 16:14:18 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id y11so4000990wrt.6 for ; Wed, 08 Jan 2020 08:14:18 -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:content-transfer-encoding; bh=T8imZVmEbIUQcvUZ1EE+oRcJzuZ0KPMrgHNp7BJ0QSg=; b=enM6XWMDHE5M+MkNpc9ZOO1MhicfWt29NMMrCC3vrHhAcgCWCljCqImyUwXTt2XIfe Pz6nNYEAih6+HDXunG654bNtiYHS3iH0yGWnIzEkgiuOdzfiQJvzLh149raNlX1prKfg aUWomrVr739T4ynQ1Rf3ywY5J+mt0swn1V5ao0pd9LIqa5CaZEeNb6qYwsuk4ynxyA0E c3Tur2/o4samxOyWNEEQQOhg2wzSfXuURJ+u4gTcdJm1Gdc2LxJD3qdFsMdwBiGUmxwF 2aLQLJlLgr4nlNlQWvmCSeBtCnr4Sw0IvXZ48gVcEAcBAOJ1bzPo9dmSEHeTofMAySIU 1B9g== 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:content-transfer-encoding; bh=T8imZVmEbIUQcvUZ1EE+oRcJzuZ0KPMrgHNp7BJ0QSg=; b=PnRA/IyI4UJbbD84WtoUX/GlNBMQty7wMDfk9HYHBRK7Mh4CcF3gj4GsUhBmOb8gGA MteCY3YlJNia7+NjDkS1vziV9m6tD4I96JjdN27VNMvjCs2RO8k81aN1fnRQ72Dd+jbW LGI6RXuFe6l4eRhtXnAZZ74CUFD47h6AQtI8kKaUKgWU2xbJzpkqTfwGoVeJ+TAHKkZx vCNfc6vDKh6Ijx0Avq/eAndpTbqxQfPpDZfHT+gXimshizGX5IvyKJCkmxDcIdqTOmNS g4sEF1eFGWYj2pCcrYddQgSRazsB2eGDSeZaJAuG1cW1q/axS/GTjpXsXTgW0iE9I9GO 4fTg== X-Gm-Message-State: APjAAAUqMhlrlFERmSb/WgC0EfepZVVNso/yoQhsZcMrXeZ/iD6Nx2a5 UIcIwzpPY4fg6lEN8RFDaNtEC+gyv9XMHGouAfGwGQ== X-Google-Smtp-Source: APXvYqxX+ZCPYIaZn5WOUOQpglwYbDOnFqB6zeYmE1WWmW4uXsTwq20H7RYpAkNLv+L1TCI5h80QzwFmNW4MZwVKVhg= X-Received: by 2002:adf:ef03:: with SMTP id e3mr5695166wro.216.1578500057012; Wed, 08 Jan 2020 08:14:17 -0800 (PST) MIME-Version: 1.0 References: <20191220184955.223741-1-glider@google.com> <20191220184955.223741-41-glider@google.com> <20191220191840.GA11160@google.com> In-Reply-To: <20191220191840.GA11160@google.com> From: Alexander Potapenko Date: Wed, 8 Jan 2020 17:14:05 +0100 Message-ID: Subject: Re: [PATCH RFC v4 40/42] kmsan: ext4: skip block merging logic in ext4_mpage_readpages for KMSAN To: Eric Biggers Cc: "Theodore Ts'o" , Andreas Dilger , Vegard Nossum , Dmitry Vyukov , Marco Elver , Andrey Konovalov , Linux Memory Management List , Al Viro , Andrew Morton , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , David Miller , Dmitry Torokhov , 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 , Matthew Wilcox , "Michael S. Tsirkin" , Michal Hocko , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , Thomas Gleixner , Vasily Gorbik , Wolfram Sang Content-Type: text/plain; charset="UTF-8" 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: > Why is ext4 special here? Wouldn't other filesystems need this too? ext4 isn't special, it's just the FS we're using on syzbot. > Is it possible the problem is the page merging logic in bio_add_page()? > Maybe we need something like: > > diff --git a/block/bio.c b/block/bio.c > index a5d75f6bf4c7e..9449a1e571ee7 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -646,6 +646,8 @@ static inline bool page_is_mergeable(const struct bio= _vec *bv, > *same_page =3D ((vec_end_addr & PAGE_MASK) =3D=3D page_addr); > if (!*same_page && pfn_to_page(PFN_DOWN(vec_end_addr)) + 1 !=3D p= age) > return false; > + if (!*same_page && IS_ENABLED(CONFIG_KMSAN)) > + return false; > return true; > } > This one appears to work, thanks! I'll pick it for v5. --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg