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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 05EAFC433E0 for ; Thu, 4 Mar 2021 21:06:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 73F6B64F6F for ; Thu, 4 Mar 2021 21:06:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73F6B64F6F 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 C8A1A6B0005; Thu, 4 Mar 2021 16:06:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C13BE6B0006; Thu, 4 Mar 2021 16:06:01 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A667B6B0007; Thu, 4 Mar 2021 16:06:01 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0241.hostedemail.com [216.40.44.241]) by kanga.kvack.org (Postfix) with ESMTP id 7A3E06B0005 for ; Thu, 4 Mar 2021 16:06:01 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 24AC8183475C1 for ; Thu, 4 Mar 2021 21:06:01 +0000 (UTC) X-FDA: 77883424122.17.E0BFEDE Received: from mail-qk1-f182.google.com (mail-qk1-f182.google.com [209.85.222.182]) by imf07.hostedemail.com (Postfix) with ESMTP id 77E01A0009F2 for ; Thu, 4 Mar 2021 21:06:00 +0000 (UTC) Received: by mail-qk1-f182.google.com with SMTP id z190so29405484qka.9 for ; Thu, 04 Mar 2021 13:06:00 -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; bh=lgdkSDcMMDWh1SRt3hQoa5/TwUrpy7W6CPuK58HsLUg=; b=E1DX7PZs5hFH2/Uww4LEeP0Z3hUElD/Z50FBpEidIfYNm73tdl4HxZ7ZgUGTCbOf8G Cae6dxwro3QySC0N3Md6i6iwtLazR3+zhoQ++LMM/8MEFu3SqIyOxjVC9yySHR6WnLop YUSxz1LtpVtp0V2gOIE68CUHxXaEP7xQv6mz/+ReaPio9y+JmYoroR+JG8aBzu6pMSdU Ybav276o3MN9TyPflzCLQboFY6S0hEtDC/CrSpLpJH5J6MkMBNrSR9wADMO3AesrMEHB Ofa+A99/jMNz7fLDNej/W+t3K36ZD4ADNbt4dpcDDDopRuvEOqnah44F0bmmLn9cQEmx AocQ== 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; bh=lgdkSDcMMDWh1SRt3hQoa5/TwUrpy7W6CPuK58HsLUg=; b=XH2tbNZLh5W+5XVLaKhiIg0Zlz579ST6prwA6SzMlXgk2yySvchOQAmBnoeVivyOeb 2uA8gWoCTOYve2vo5Ih0EfMIh86vUlD0fQg4Uk+jXJxUFYl6fIjmYQlcdWcOvU7dwzqj 0dTXwKcZRGT1HpvFPYisO0y2yUuB84GxJpGHnkm2QeLPs7/vkT3Dis8WqAwY5pCPMG95 aIVnP9xFG3n3jHrlYtsl58bdE/fqhQTl4GcGF5oAlO5AlrWs1xhrO01acSg66f/7QUuE qn7Gldoj+wJC+n486k8SWE+UXAJF2FtCnTmZNazwowidMgzQhyGh9qv9Jcb9W8LMsLkp AKPQ== X-Gm-Message-State: AOAM530/vVPbZbGXt3V7X7bXzyLKvyj2AahUfldEtgh9kysZT17oz/T5 a7t39OkI8fuGQlkg5LBU9vCKXjkBSpDYXEua5NNgbw== X-Google-Smtp-Source: ABdhPJzOwE+1Sg5OvskywxdoiGHdv7NJRbHDt9/fENzJUfNvdNmhW6cIta6mx85BXuIJsvrgTFTZ/pRK4X/+/EhYqMs= X-Received: by 2002:a05:620a:1353:: with SMTP id c19mr6192822qkl.392.1614891959772; Thu, 04 Mar 2021 13:05:59 -0800 (PST) MIME-Version: 1.0 References: <20210304205256.2162309-1-elver@google.com> In-Reply-To: <20210304205256.2162309-1-elver@google.com> From: Alexander Potapenko Date: Thu, 4 Mar 2021 22:05:48 +0100 Message-ID: Subject: Re: [PATCH mm] kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations To: Andrew Morton Cc: Dmitriy Vyukov , Andrey Konovalov , Jann Horn , LKML , Linux Memory Management List , kasan-dev , Marco Elver Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 8f73ioezw8ba6y8wo4bs3rijogkpzriq X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 77E01A0009F2 Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf07; identity=mailfrom; envelope-from=""; helo=mail-qk1-f182.google.com; client-ip=209.85.222.182 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614891960-315074 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 Thu, Mar 4, 2021 at 9:53 PM Marco Elver wrote: > > cache_alloc_debugcheck_after() performs checks on an object, including > adjusting the returned pointer. None of this should apply to KFENCE > objects. While for non-bulk allocations, the checks are skipped when we > allocate via KFENCE, for bulk allocations cache_alloc_debugcheck_after() > is called via cache_alloc_debugcheck_after_bulk(). @Andrew, is this code used by anyone? As far as I understand, it cannot be enabled by any config option, so nobody really tests it. If it is still needed, shall we promote #if DEBUGs in slab.c to a separate config option, or maybe this code can be safely removed? Alex