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 7B84FC433FE for ; Mon, 16 May 2022 10:23:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242581AbiEPKXu (ORCPT ); Mon, 16 May 2022 06:23:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242559AbiEPKXS (ORCPT ); Mon, 16 May 2022 06:23:18 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 891AAE085 for ; Mon, 16 May 2022 03:23:08 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id x12so13659136pgj.7 for ; Mon, 16 May 2022 03:23:08 -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=E1HA7mTkokdfUBOTOx/UT/zRHvpwkRZMgaF2tqkC7Lc=; b=I0/JeIClQwBorAMPSgPnbRPgkEOQC7Mr3Pms0T10DCu0fw6VhfTLuxj7jOtLphdp95 2qMARSAiX5pBAbL4qdkFvFE3g3Mx2OLrOD61gNNw6loxErIQzZWg3y9F4UGd6h2GccgH BmINNSNVBA9veX8ta2i94KfzCly2VD/huBZRwQEtAveOHwDk4R3SeBoO2NUUarW9PqKG EEf5fPmZDyWYHJBD4VCbMznNow+dRJL5kc9OAiFvqAIbycA0Tf2lPHNw0UPuCPu0GVmJ zX33ayCnncNEV7Zu+mW3ITLLR9kOnBrXxJNprV2Oqql25YtAlOAzqgZqziQwIrhRKC3s Ke7Q== 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=E1HA7mTkokdfUBOTOx/UT/zRHvpwkRZMgaF2tqkC7Lc=; b=uwDU4IhcYAZU83x4xkG3AQKjIlSXLDT8cGJBk79rF0FfA93OzL5A5sFy2PpyXPeQc4 tIHCb8EiH5+pAKBvOB9XUP/hfYi63c2Z6X+rXD2wDc1MpPOuTuovo2UsvMsb7apWjvbp 3OLi/r0CffkYmBORhfmSLG+HiFShOrCPb4Kf8mXbIcfD/2j0COG5QefVO4rg2LivNz/3 NJjM9PWE19V8RnR7D9Qlta4PG97/DgNFTUtR5AkuJBR/P+7HzQIQNqEYUIwdsmpR37KI 9xS13S04/ExQzGvDEghy1vjVYOewED65lknMunNCgap84rS/RkSXP9rK4Yn4AuUPfHC2 uXcA== X-Gm-Message-State: AOAM532iGQRJR+zL6GggHvV96V9SPi9CFry8/wbQZru+mRP3bStewog/ 21qMiN+9xwyLD6KI9GT+dxJGJA== X-Google-Smtp-Source: ABdhPJx+le9SIrFuAU5RA8TqPnUWh9duy4U2Dkz5aeGmIOp6I4BVYjVIVE/iqBYV3UcV8r9rt34QsA== X-Received: by 2002:a05:6a00:1492:b0:50e:11ae:f62f with SMTP id v18-20020a056a00149200b0050e11aef62fmr17044341pfu.43.1652696588092; Mon, 16 May 2022 03:23:08 -0700 (PDT) Received: from FVFYT0MHHV2J.bytedance.net ([139.177.225.234]) by smtp.gmail.com with ESMTPSA id i9-20020aa79089000000b0050dc76281e4sm6472731pfa.190.2022.05.16.03.23.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 May 2022 03:23:07 -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 v12 1/7] mm: hugetlb_vmemmap: disable hugetlb_optimize_vmemmap when struct page crosses page boundaries Date: Mon, 16 May 2022 18:22:05 +0800 Message-Id: <20220516102211.41557-2-songmuchun@bytedance.com> X-Mailer: git-send-email 2.32.1 (Apple Git-133) In-Reply-To: <20220516102211.41557-1-songmuchun@bytedance.com> References: <20220516102211.41557-1-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 Reviewed-by: Mike Kravetz Acked-by: David Hildenbrand --- 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