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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FE9BC433EF for ; Fri, 3 Dec 2021 00:52:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238162AbhLCAzy (ORCPT ); Thu, 2 Dec 2021 19:55:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232416AbhLCAzx (ORCPT ); Thu, 2 Dec 2021 19:55:53 -0500 Received: from mail-pg1-x533.google.com (mail-pg1-x533.google.com [IPv6:2607:f8b0:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64084C06174A; Thu, 2 Dec 2021 16:52:30 -0800 (PST) Received: by mail-pg1-x533.google.com with SMTP id k4so1394090pgb.8; Thu, 02 Dec 2021 16:52:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=KcgckVJBk609C9n8WlYPxKWxBCCyIgqINt/uZGi6A0Y=; b=Ctf7ofl9Xke/PvNfOa+Vrw+j8ZBmzqUrFn63JewI2pdb1XRMsZgcYJ6ssqVhQpeDjA ya/eT9D/t9b86F/AArvhA/u4vb7Q466qgo9KzGmBFPZijZkkoSob/z+47kRcGLqgoLcX bsKy2XDc+XW2Z3hJyPDbt5ekMsag8vEQ2CepLHEGWHzbT4FUP8ejDg9HntELO6U/kHXv 0lfZVQR7cTvYiPYD9S0BPTPNA7HKN4I5EniGd53Riw/4BkWX0Rzro4VxzMSJ2yNh1zWV Ss04cFrELxmFNzr+xgR2eQO2siyrMfdD3g7WfN8Jk6hkDnUt2W+67yQTSa55mAdVQ+Wq eSag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=KcgckVJBk609C9n8WlYPxKWxBCCyIgqINt/uZGi6A0Y=; b=EVLha84H23tWr5XtmEvHBREgXMfFIiowzXozBrc2j64U60xK/dFEYOdeQJ5u5c8htH Bk+3UeN8vyQgMmKkKDV7togqu60D/uBXzgD6cswPZ4prr7j9ErjJRkJQNs0X7Ve9mZk1 LMOxGMnRUvgp49fthwhGslaXQ5UC5ASd/pClocUfMhvclOvBfDwyZfZZs5aeRWKfUO+w bc4EzgU/od2yurE2dQzsZJmyasOr1T52Dx7nhKYi7LihFaVnXCvjrpW4Mo6Jdvvkp3hd r6eYvvkVjsHE2weaqyeku/u5/Au1yXUQy62zwgJGtKoZIcoLfFnxXWjVtLYN7NrhnDYl ljiQ== X-Gm-Message-State: AOAM532exG8ThJcBTM7je0AFQL5NmZ8MBV7wqRYzNVpwdMk+Ann+APYT F/+ZkDRGzz5V4soKNYJYMVM= X-Google-Smtp-Source: ABdhPJy0wAKaq2tyZW6eEKVEZ01mPalVC9neiDt4H5evhXCCzzA5axCTHMxBIQfQZL4+VtxXQMlS3g== X-Received: by 2002:a05:6a00:15ca:b0:49f:d22b:afff with SMTP id o10-20020a056a0015ca00b0049fd22bafffmr15996509pfu.35.1638492749937; Thu, 02 Dec 2021 16:52:29 -0800 (PST) Received: from localhost ([103.99.179.247]) by smtp.gmail.com with ESMTPSA id h26sm652480pgm.68.2021.12.02.16.52.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Dec 2021 16:52:29 -0800 (PST) Date: Fri, 3 Dec 2021 08:52:24 +0800 From: Calvin Zhang To: Catalin Marinas Cc: Andrew Morton , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Rob Herring , Frank Rowand , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org Subject: Re: [PATCH] mm: kmemleak: Ignore kmemleak scanning on CMA regions Message-ID: References: <20211126024711.54937-1-calvinzhang.cool@gmail.com> <20211127160718.54e82aa93c977a367404a9e3@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 02, 2021 at 06:11:12PM +0000, Catalin Marinas wrote: >On Sun, Nov 28, 2021 at 09:50:53AM +0800, Calvin Zhang wrote: >> On Sat, Nov 27, 2021 at 04:07:18PM -0800, Andrew Morton wrote: >> >On Fri, 26 Nov 2021 10:47:11 +0800 Calvin Zhang wrote: >> >> Just like this: >> >> commit 620951e27457 ("mm/cma: make kmemleak ignore CMA regions"). >> >> >> >> Add kmemleak_ignore_phys() for CMA created from of reserved node. >[...] >> >The 620951e27457 changelog says "Without this, the kernel crashes...". >> >Does your patch also fix a crash? If so under what circumstances and >> >should we backport this fix into -stable kernels? >> >> No crash occurred. 620951e27457 avoids crashes caused by accessing >> highmem and it was fixed later. Now kmemleak_alloc_phys() and >> kmemleak_ignore_phys() skip highmem. This patch is based on the >> point that CMA regions don't contain pointers to other kmemleak >> objects, and ignores CMA regions from reserved memory as what >> 620951e27457 did. > >Note that kmemleak_ignore() only works if there was a prior >kmemleak_alloc() on that address range. With the previous commit we get >this via the memblock_alloc_range() but I fail to see one on the >rmem_cma_setup() path. rmem is from memblock_reserve() or early_init_dt_alloc_reserved_memory_arch() kmemleak_alloc() is not called in the first case. And It's bad to add one. I think all the reserved regions should be allocated from memblock without kmemleak_alloc() and let rmem handler choose to add it as kmemleak object by kmemleak_alloc(). Because MEMBLOCK_ALLOC_NOLEAKTRACE conflicts with range parameter in memlbock_alloc_* series, all reserved regions and default CMA region are allocated with kmemleak_alloc(). I think it's better to add memblock_alloc_* series a spearate flag paramter (like "NOLEAKTRACE") instead of encoding MEMBLOCK_ALLOC_NOLEAKTRACE in `end` parameter. -- Calvin