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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8064DC433DB for ; Wed, 17 Mar 2021 08:53:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D13764F26 for ; Wed, 17 Mar 2021 08:53:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229559AbhCQIw4 (ORCPT ); Wed, 17 Mar 2021 04:52:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:45142 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229510AbhCQIwb (ORCPT ); Wed, 17 Mar 2021 04:52:31 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0ECE364E27; Wed, 17 Mar 2021 08:52:28 +0000 (UTC) Date: Wed, 17 Mar 2021 08:52:26 +0000 From: Catalin Marinas To: Marco Elver Cc: akpm@linux-foundation.org, glider@google.com, dvyukov@google.com, andreyknvl@google.com, jannh@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com, Luis Henriques Subject: Re: [PATCH mm] kfence: make compatible with kmemleak Message-ID: <20210317085225.GA12269@arm.com> References: <20210317084740.3099921-1-elver@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210317084740.3099921-1-elver@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 17, 2021 at 09:47:40AM +0100, Marco Elver wrote: > Because memblock allocations are registered with kmemleak, the KFENCE > pool was seen by kmemleak as one large object. Later allocations through > kfence_alloc() that were registered with kmemleak via > slab_post_alloc_hook() would then overlap and trigger a warning. > Therefore, once the pool is initialized, we can remove (free) it from > kmemleak again, since it should be treated as allocator-internal and be > seen as "free memory". > > The second problem is that kmemleak is passed the rounded size, and not > the originally requested size, which is also the size of KFENCE objects. > To avoid kmemleak scanning past the end of an object and trigger a > KFENCE out-of-bounds error, fix the size if it is a KFENCE object. > > For simplicity, to avoid a call to kfence_ksize() in > slab_post_alloc_hook() (and avoid new IS_ENABLED(CONFIG_DEBUG_KMEMLEAK) > guard), just call kfence_ksize() in mm/kmemleak.c:create_object(). > > Reported-by: Luis Henriques > Cc: Catalin Marinas > Signed-off-by: Marco Elver Reviewed-by: Catalin Marinas