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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 527C3C433FE for ; Thu, 2 Dec 2021 18:11:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B6E1D6B0075; Thu, 2 Dec 2021 13:11:28 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B1C416B0078; Thu, 2 Dec 2021 13:11:28 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A0A9A6B007B; Thu, 2 Dec 2021 13:11:28 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 91A316B0075 for ; Thu, 2 Dec 2021 13:11:28 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 4B1D41845F487 for ; Thu, 2 Dec 2021 18:11:18 +0000 (UTC) X-FDA: 78873646236.03.A5AD82F Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf02.hostedemail.com (Postfix) with ESMTP id B096380005 for ; Thu, 2 Dec 2021 18:11:17 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9BC341435; Thu, 2 Dec 2021 10:11:16 -0800 (PST) Received: from arm.com (arrakis.cambridge.arm.com [10.1.196.175]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2FEB23F766; Thu, 2 Dec 2021 10:11:15 -0800 (PST) Date: Thu, 2 Dec 2021 18:11:12 +0000 From: Catalin Marinas To: Calvin Zhang 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: X-Rspamd-Queue-Id: B096380005 X-Stat-Signature: qs664431qzjqbo4a4mmrgc7aiwgyzrj5 Authentication-Results: imf02.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf02.hostedemail.com: domain of catalin.marinas@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=catalin.marinas@arm.com X-Rspamd-Server: rspam02 X-HE-Tag: 1638468677-658562 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: 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. -- Catalin