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 703ADC433FE for ; Fri, 29 Apr 2022 12:18:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358998AbiD2MWC (ORCPT ); Fri, 29 Apr 2022 08:22:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238748AbiD2MV5 (ORCPT ); Fri, 29 Apr 2022 08:21:57 -0400 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29991B3C75 for ; Fri, 29 Apr 2022 05:18:39 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id s137so6389971pgs.5 for ; Fri, 29 Apr 2022 05:18:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Sb7cKusP7HmwEMFLljkRCnuPfmcRLCQDQWff8XX78N4=; b=ujf++oGTRkcmvgbJDzD35LqcmXlDmxx9MV7JBsCDJlobs2RrJt7Oin3Tp6YJWZSb4v 9pD3a81OGs+Rvr9bhGzIguAqbwWgBnZtv6XULJJozikDR56kziPLN1jhnHZTf/HusSzV w63qNhi0UKdgf6Q9Fq+cz+V4qw1+H3gfd1FB5CgYLwAD7FKIg+U2A3PKdV62na10dGaP uHFViPBg8CIa2xG7vAItmaI0KXTl/Td/1o3ipN73lzlFryjc/F+CyUtsT9v0X6W/1RuW a9MOjWqpYGACasXXh7MNQMe9KERCZSJqchBd9Dvm3EvJmQbv8dV4Tg9o5hNkY+lx9T2W j4pQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Sb7cKusP7HmwEMFLljkRCnuPfmcRLCQDQWff8XX78N4=; b=04nGiA+4o4uFBppZ9G/9weE+ZvaJDkgMmMBiiEqGX+fODmFQX02iwiwFFWacm7m5iK JlnlThA+F+puUE6BpoVqpSa2QfgqC2mI8261JHL4s/+eH+XojfQCbHVBuLf2tBXKD89r mNZhuxch4Isz50CaaoObW7s2UCBPHrN5MGMmSR0hlO8Bdgs94BKfPV1/wHN0oSDt1jpL TBV6cGymkTJ9szGE6BO9v7PXvoyW6L2WVSmUY1DBS5726KAPkLnSJK8LLjiVO4rOPpm7 1D56MF4LPijRGbCYPfcU/H+5G90WOtfKfYWaykA3pn9Mzw6L62ZndPjMDRPwOXYxHq7c h4kA== X-Gm-Message-State: AOAM532h+aoyt0n0rULoJMTfrgpb2LpsbJ+MyW9FlcE3tPaWTFA5s7s8 fBtJ/wUdqDhmoqCLg4KdMKN+Fg== X-Google-Smtp-Source: ABdhPJyV4XCJ1uaJg+Pde1nxM1j4YKLXpIc83hyQsnEeiM1URERFxVgDV1/VvFaifwpneZ3ujEuceg== X-Received: by 2002:a63:d145:0:b0:3c1:4ba0:d890 with SMTP id c5-20020a63d145000000b003c14ba0d890mr10020401pgj.607.1651234718613; Fri, 29 Apr 2022 05:18:38 -0700 (PDT) Received: from FVFYT0MHHV2J.bytedance.net ([139.177.225.239]) by smtp.gmail.com with ESMTPSA id k11-20020a056a00168b00b004f7e1555538sm3101421pfc.190.2022.04.29.05.18.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Apr 2022 05:18:38 -0700 (PDT) From: Muchun Song To: corbet@lwn.net, mike.kravetz@oracle.com, akpm@linux-foundation.org, mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com, osalvador@suse.de, david@redhat.com, masahiroy@kernel.org Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, smuchun@gmail.com, Muchun Song Subject: [PATCH v9 1/4] mm: hugetlb_vmemmap: disable hugetlb_optimize_vmemmap when struct page crosses page boundaries Date: Fri, 29 Apr 2022 20:18:13 +0800 Message-Id: <20220429121816.37541-2-songmuchun@bytedance.com> X-Mailer: git-send-email 2.32.0 (Apple Git-132) In-Reply-To: <20220429121816.37541-1-songmuchun@bytedance.com> References: <20220429121816.37541-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the size of "struct page" is not the power of two but with the feature of minimizing overhead of struct page associated with each HugeTLB is enabled, then the vmemmap pages of HugeTLB will be corrupted after remapping (panic is about to happen in theory). But this only exists when !CONFIG_MEMCG && !CONFIG_SLUB on x86_64. However, it is not a conventional configuration nowadays. So it is not a real word issue, just the result of a code review. But we cannot prevent anyone from configuring that combined configure. This hugetlb_optimize_vmemmap should be disable in this case to fix this issue. Signed-off-by: Muchun Song --- mm/hugetlb_vmemmap.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 29554c6ef2ae..6254bb2d4ae5 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -28,12 +28,6 @@ EXPORT_SYMBOL(hugetlb_optimize_vmemmap_key); static int __init hugetlb_vmemmap_early_param(char *buf) { - /* We cannot optimize if a "struct page" crosses page boundaries. */ - if (!is_power_of_2(sizeof(struct page))) { - pr_warn("cannot free vmemmap pages because \"struct page\" crosses page boundaries\n"); - return 0; - } - if (!buf) return -EINVAL; @@ -119,6 +113,12 @@ void __init hugetlb_vmemmap_init(struct hstate *h) if (!hugetlb_optimize_vmemmap_enabled()) return; + if (!is_power_of_2(sizeof(struct page))) { + pr_warn_once("cannot optimize vmemmap pages because \"struct page\" crosses page boundaries\n"); + static_branch_disable(&hugetlb_optimize_vmemmap_key); + return; + } + vmemmap_pages = (nr_pages * sizeof(struct page)) >> PAGE_SHIFT; /* * The head page is not to be freed to buddy allocator, the other tail -- 2.11.0