From nobody Thu Sep 11 16:07:35 2025 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 88718C6379F for ; Sat, 18 Feb 2023 00:29:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229972AbjBRA35 (ORCPT ); Fri, 17 Feb 2023 19:29:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229773AbjBRA3X (ORCPT ); Fri, 17 Feb 2023 19:29:23 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D8F66C00F for ; Fri, 17 Feb 2023 16:29:01 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id k72-20020a25244b000000b0083fa6f15c2fso1931074ybk.16 for ; Fri, 17 Feb 2023 16:29:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=0wSMKMWzwfQ8fLAFHXt0NmwJTi1H1o52qxxMn528B3Y=; b=axPHyxy1GBdJ3j5NWk4sW5NYHawOKf9AoibB4HV5FfIZJydc97adJIODrPR+QPgxNK nr00e5FMgkdE8K907sG4ZDoHr5Lt8bsvRMbzhBZu9D/vDZvX+woxXErLOoWLQSU7lSB3 ColvlhjaPZZh6IxAnrEln+IITIxYCmy04Z2l1SbzE3B6POnZJUSMCAYWIRaT1Yw6pXLR Wq0cbmdstbtdCR3d2d+bJjVqqNZDwx8tE8yRYgFkpy+28U20Db+9VK0iOYSso+pD2sG8 OJeoIbKDbGGxUqdzljTj52m+1rUrxcY+G67jmbfYWqpHTo5y/BK5aqWA0UQIkWR55NRP GAqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=0wSMKMWzwfQ8fLAFHXt0NmwJTi1H1o52qxxMn528B3Y=; b=M9PdICCwevoqsB+YVTZsRvQA61+M95wXb0iiBN3kIbODe4IrbG7LRQmgVpBlmVrqaS 3PDMXLyKm5+6I0IXX1hKLyLZdou2vq95clAAR4aCJGS/qRCvtcAjtqz40z7Y5lMaK9KV l0E9+fyxGoU4kbf198vOow1giRLatW4yVE/bHiPLqaRhoWLyrec8sTlUMOxnQyG7V4Yl OJNMLEeAKhvBq3QytuB34asEcjSPnnVWKLhZTdWfg7zb7hpD1jpUn15fOct9SWRFBABH WcWWYLlpe5zA91qiP5lJn4J+vmB984/78vdtDnOS9Fc/0Q9vkYn9A9algB6N+kmL6hzW Aa4g== X-Gm-Message-State: AO0yUKUGGrCD7M5JpPpo+d/M2EdLTg+ulxaUvXg1m2BkERda9pyfJIUJ Uu30ZxWxXHgh0wnMwBQ7wgQAQC5hRf6PGl5/ X-Google-Smtp-Source: AK7set8P4IRNjQRV3GSaApBMgcJvUr/kZLWUTr2MSxmgTV4ZqD4cm7y5M6XYvFN0JDI5vO1MJ3hc9iawF3gnH6MW X-Received: from jthoughton.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2a4f]) (user=jthoughton job=sendgmr) by 2002:a05:690c:38d:b0:533:a15a:d33e with SMTP id bh13-20020a05690c038d00b00533a15ad33emr73114ywb.5.1676680140092; Fri, 17 Feb 2023 16:29:00 -0800 (PST) Date: Sat, 18 Feb 2023 00:27:50 +0000 In-Reply-To: <20230218002819.1486479-1-jthoughton@google.com> Mime-Version: 1.0 References: <20230218002819.1486479-1-jthoughton@google.com> X-Mailer: git-send-email 2.39.2.637.g21b0678d19-goog Message-ID: <20230218002819.1486479-18-jthoughton@google.com> Subject: [PATCH v2 17/46] hugetlbfs: do a full walk to check if vma maps a page From: James Houghton To: Mike Kravetz , Muchun Song , Peter Xu , Andrew Morton Cc: David Hildenbrand , David Rientjes , Axel Rasmussen , Mina Almasry , "Zach O'Keefe" , Manish Mishra , Naoya Horiguchi , "Dr . David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Frank van der Linden , Jiaqi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, James Houghton Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Because it is safe to do so, do a full high-granularity page table walk to check if the page is mapped. Signed-off-by: James Houghton diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index cfd09f95551b..c0ee69f0418e 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -386,17 +386,24 @@ static void hugetlb_delete_from_page_cache(struct fol= io *folio) static bool hugetlb_vma_maps_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) { - pte_t *ptep, pte; + pte_t pte; + struct hugetlb_pte hpte; =20 - ptep =3D hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma))); - if (!ptep) + if (hugetlb_full_walk(&hpte, vma, addr)) return false; =20 - pte =3D huge_ptep_get(ptep); + pte =3D huge_ptep_get(hpte.ptep); if (huge_pte_none(pte) || !pte_present(pte)) return false; =20 - if (pte_page(pte) =3D=3D page) + if (unlikely(!hugetlb_pte_present_leaf(&hpte, pte))) + /* + * We raced with someone splitting us, and the only case + * where this is impossible is when the pte was none. + */ + return false; + + if (compound_head(pte_page(pte)) =3D=3D page) return true; =20 return false; --=20 2.39.2.637.g21b0678d19-goog