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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 06C01C2D0C6 for ; Wed, 11 Dec 2019 17:12:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDBE92073D for ; Wed, 11 Dec 2019 17:12:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HcsFv2I+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730967AbfLKRM4 (ORCPT ); Wed, 11 Dec 2019 12:12:56 -0500 Received: from mail-wr1-f65.google.com ([209.85.221.65]:40998 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729512AbfLKRM4 (ORCPT ); Wed, 11 Dec 2019 12:12:56 -0500 Received: by mail-wr1-f65.google.com with SMTP id c9so24906997wrw.8 for ; Wed, 11 Dec 2019 09:12:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=87+nbO7EsRQpe1wmSikO8vry0s4iwAAY074PAWZUn2w=; b=HcsFv2I+5GpN8tthV67smYXfufVMlWaYkFgMpkaFzDGdfjp3TGIZLjlMspfT4yePt8 dFSnPi7iQLJduP3wwTLzsCAM9YhX++2smHKxYvO/dNtL0r/Cfx0wTLsJASTpLU33FaFd vV2cmdcUjYag4Yspdav4q6tvir6wnV5/6ZWzOCYOIEzS2dVUKOv+w6eTtgQxfZSIyIeI tY8Q3yuYWrKD7iczRVzQMwyU0sz8+NBZyQZj5hcREfBBKevQUlvjvfh2mRKNXC9eaaid HtqBvKiHPHM4TD/9eJI85G//q4Q5ANEs2JUVrHz+jwzjo7KLz3C4KxqzjOSCx9RpkIFM jWWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=87+nbO7EsRQpe1wmSikO8vry0s4iwAAY074PAWZUn2w=; b=Fu7JxZsfeCf00OWFha/Dnnt9EE4glCwehb2mSkeQyBVeKg5DgwOcvHGTwi4EBbCW9C aht1uos7K+6Vr6GM60Lb+Qh/X6j5jys2sVX0u4kFmNTo6Y2r8xzG8KH2QCfFQa48WP/q 27CclF8g86cVlWPBZqv5Y8daVikzj4yWqUVGUSs5FPPnvbdMqFdkuQHdm69PyZ2eFb6F 24P5oegwBZN7RyYZaY39s2WeswvoR5zSY6A9N7txBICLlCihnkRL/bkQYFOTg857SF6a 7KW8Qp0xr3UhWg4laG2wHyhqiBQb0YjdRwoCedvA3SLXW4rCE4IEVqPPZRArV3avWJNk jAAQ== X-Gm-Message-State: APjAAAVHyZO/WEGpKgKG1gL6bJnG691Yt3LmiWJQ+oiIHeI05h5+ppVw X8FWAhmz6pIqNwlKrj8HOPr+37pa X-Google-Smtp-Source: APXvYqweJn+YpFwyn3LDIvxX4iMjbKa0WcfWqrhUUtEz4LpLSFHJwQKsC27YRGAVas14wLiu98uruA== X-Received: by 2002:adf:df03:: with SMTP id y3mr996018wrl.260.1576084374686; Wed, 11 Dec 2019 09:12:54 -0800 (PST) Received: from ltop.local ([2a02:a03f:40f6:4600:d98a:4956:14c2:2b5d]) by smtp.gmail.com with ESMTPSA id 2sm2973189wrq.31.2019.12.11.09.12.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Dec 2019 09:12:53 -0800 (PST) Date: Wed, 11 Dec 2019 18:12:52 +0100 From: Luc Van Oostenryck To: Steven Price Cc: kbuild test robot , Mark Rutland , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, "H. Peter Anvin" , Will Deacon , "Liang, Kan" , x86@kernel.org, Ingo Molnar , Arnd Bergmann , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, kbuild-all@lists.01.org, Ard Biesheuvel , linux-kernel@vger.kernel.org, James Morse , Andrew Morton Subject: Re: [PATCH v16 13/25] mm: pagewalk: Don't lock PTEs for walk_page_range_novma() Message-ID: <20191211171252.fdbdqn2nrze637gm@ltop.local> References: <20191206135316.47703-14-steven.price@arm.com> <201912101842.KIXI4yCg%lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 11, 2019 at 03:54:06PM +0000, Steven Price wrote: > On 10/12/2019 11:23, kbuild test robot wrote: > >>> include/linux/spinlock.h:378:9: sparse: sparse: context imbalance in 'walk_pte_range' - unexpected unlock > > I believe this is a false positive (although the trace here is useless). > This patch adds a conditional lock/unlock: > > pte = walk->no_vma ? pte_offset_map(pmd, addr) : > pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > ... > if (!walk->no_vma) > spin_unlock(ptl); > pte_unmap(pte); > > I'm not sure how to match sparse happy about that. Is the only option to > have two versions of the walk_pte_range() function? One which takes the > lock and one which doesn't. Yes. -- Luc 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=-0.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 C640EC43603 for ; Wed, 11 Dec 2019 17:13:01 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9D8B72054F for ; Wed, 11 Dec 2019 17:13:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="rc6h2tqy"; 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Wed, 11 Dec 2019 09:12:53 -0800 (PST) Date: Wed, 11 Dec 2019 18:12:52 +0100 From: Luc Van Oostenryck To: Steven Price Subject: Re: [PATCH v16 13/25] mm: pagewalk: Don't lock PTEs for walk_page_range_novma() Message-ID: <20191211171252.fdbdqn2nrze637gm@ltop.local> References: <20191206135316.47703-14-steven.price@arm.com> <201912101842.KIXI4yCg%lkp@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191211_091256_810845_D8DA2C74 X-CRM114-Status: GOOD ( 13.14 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, "H. Peter Anvin" , Will Deacon , "Liang, Kan" , kbuild test robot , x86@kernel.org, Ingo Molnar , Arnd Bergmann , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Borislav Petkov , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, kbuild-all@lists.01.org, Ard Biesheuvel , linux-kernel@vger.kernel.org, James Morse , Andrew Morton Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Dec 11, 2019 at 03:54:06PM +0000, Steven Price wrote: > On 10/12/2019 11:23, kbuild test robot wrote: > >>> include/linux/spinlock.h:378:9: sparse: sparse: context imbalance in 'walk_pte_range' - unexpected unlock > > I believe this is a false positive (although the trace here is useless). > This patch adds a conditional lock/unlock: > > pte = walk->no_vma ? pte_offset_map(pmd, addr) : > pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > ... > if (!walk->no_vma) > spin_unlock(ptl); > pte_unmap(pte); > > I'm not sure how to match sparse happy about that. Is the only option to > have two versions of the walk_pte_range() function? One which takes the > lock and one which doesn't. Yes. -- Luc _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel