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=-26.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,URIBL_RED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 96089C11F67 for ; Wed, 14 Jul 2021 09:22:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7AEBA61369 for ; Wed, 14 Jul 2021 09:22:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238797AbhGNJZU (ORCPT ); Wed, 14 Jul 2021 05:25:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238291AbhGNJZT (ORCPT ); Wed, 14 Jul 2021 05:25:19 -0400 Received: from mail-wr1-x44a.google.com (mail-wr1-x44a.google.com [IPv6:2a00:1450:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4E349C061760 for ; Wed, 14 Jul 2021 02:22:28 -0700 (PDT) Received: by mail-wr1-x44a.google.com with SMTP id h15-20020adffd4f0000b0290137e68ed637so1146555wrs.22 for ; Wed, 14 Jul 2021 02:22:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=Qyc6ohzjuGWO87gzL/Z+Is02vLbY2suPFPQ1nEFYzSU=; b=AgQnCrNOd7i5dBNRA+Pqzh0QH1Aavvx/jvqVMlgotATgmfiQ9tML534h2Yt0Wp6UVD dPCrTzqm3k828aTupcVUKNvi1boNjXELkbENaolWJCSx3FLNUG5vZY14y1N3UaxiQka5 +q+oEgzkBkNs6xz8EJ6+xX00OSYkkSX47ur8ATJ2uzpAtZh4TbLoyw6PlDiOrEPI7ePs h3eyPY50SvRZx/kOkqepKO3iRLDAsYfLa6LAL+akoR+aYpsPu7dxAcRztxsEHgLOr6OL Zx1N3zurNs4uK7PulQxbL3PGcncwcgxZBhtst0DHt/kWg1ICnEil0BewSj5afs/vQH71 JD7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=Qyc6ohzjuGWO87gzL/Z+Is02vLbY2suPFPQ1nEFYzSU=; b=RCCKUNdYCKIGATxxCzb6qFTpujfHVyjWTBEzOt5KvuFVES2tOGs5l2BemchiezdPuI ewxR+XMplO9XuznNDo2Mw4EZhZjnXumq6zyiyIzSWWIQEMtmXuIxHLptFBkS8ZzqPqlI hyZ/HJiZIhMsEbPS+9auyYyesIDMHdN3bGCkgJVfKAbnRSNf/VS+S4gbFyEpS5Aubfmv BbU55ph1obCVHS+0H4foMO+yS6Xa1r0Rdjb0sSnH1yhsD2N6+ZnG/OxPn98JNlyNmvMd FDp+IKErucnbS5wxak1oGmwMvrYPTtuEhrIUyp+IS/FGtOtNNcViv2KYIcEmyib/ZXlq rKlw== X-Gm-Message-State: AOAM531Ir4p8BB2I5Y361IunkWuolfpyEVahLbBXngKp/LAlfFAr0NBs PwX5Ojt99OTXVHpofKvVfEmqKOi088w= X-Google-Smtp-Source: ABdhPJzYuKhDVZIN8Rj3HEws6Yo8UjiKSv5LM81gKwrWyru/o3IaiXXaws7mE9L6DdcQ7W3fAYE05yBPxQ4= X-Received: from glider.muc.corp.google.com ([2a00:79e0:15:13:89ec:cd11:7e8b:63fe]) (user=glider job=sendgmr) by 2002:a05:600c:2248:: with SMTP id a8mr2892376wmm.141.1626254546797; Wed, 14 Jul 2021 02:22:26 -0700 (PDT) Date: Wed, 14 Jul 2021 11:22:21 +0200 Message-Id: <20210714092222.1890268-1-glider@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.32.0.93.g670b81a890-goog Subject: [PATCH mm v5 1/2] kfence: move the size check to the beginning of __kfence_alloc() From: Alexander Potapenko To: akpm@linux-foundation.org Cc: dvyukov@google.com, elver@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, gregkh@linuxfoundation.org, jrdr.linux@gmail.com, Alexander Potapenko Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check the allocation size before toggling kfence_allocation_gate. This way allocations that can't be served by KFENCE will not result in waiting for another CONFIG_KFENCE_SAMPLE_INTERVAL without allocating anything. Suggested-by: Marco Elver Cc: Andrew Morton Cc: Dmitry Vyukov Cc: Marco Elver Cc: Greg Kroah-Hartman Cc: stable@vger.kernel.org # 5.12+ Signed-off-by: Alexander Potapenko Reviewed-by: Marco Elver --- mm/kfence/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/kfence/core.c b/mm/kfence/core.c index d7666ace9d2e4..2623ff401a104 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -733,6 +733,13 @@ void kfence_shutdown_cache(struct kmem_cache *s) void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) { + /* + * Perform size check before switching kfence_allocation_gate, so that + * we don't disable KFENCE without making an allocation. + */ + if (size > PAGE_SIZE) + return NULL; + /* * allocation_gate only needs to become non-zero, so it doesn't make * sense to continue writing to it and pay the associated contention @@ -757,9 +764,6 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) if (!READ_ONCE(kfence_enabled)) return NULL; - if (size > PAGE_SIZE) - return NULL; - return kfence_guarded_alloc(s, size, flags); } -- 2.32.0.93.g670b81a890-goog