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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 19B98C55ABD for ; Fri, 13 Nov 2020 22:19:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6C6A2223F for ; Fri, 13 Nov 2020 22:19:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="HJ+JRP0S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726541AbgKMWTK (ORCPT ); Fri, 13 Nov 2020 17:19:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726569AbgKMWRb (ORCPT ); Fri, 13 Nov 2020 17:17:31 -0500 Received: from mail-wm1-x349.google.com (mail-wm1-x349.google.com [IPv6:2a00:1450:4864:20::349]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 56A23C0617A6 for ; Fri, 13 Nov 2020 14:17:31 -0800 (PST) Received: by mail-wm1-x349.google.com with SMTP id g3so3988694wmh.9 for ; Fri, 13 Nov 2020 14:17:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=JnUxOJIynAj3uI1y+sO3DfMh7ir+WlJGNb++LFrX210=; b=HJ+JRP0S6+eUg+e42XlAvr5+D8XnjnXcbJcnVWKyhHfxILa7L2iAAlvDT5PboLOAMO kG1l/8RNcBki2ToFLLjfQpmCzzWJfCzByewGvOnmF8hNskzssMLs1TFn8KOSfIn4q3mY pqXygbWN2nTDadrTM0bUhB+aN9dG+MTmUm+b7pongo++WW3H8QKIgfaTwo+TKenrmk2i nlD1BSYO4cB+xw7HeTEqdLyArv5S/JBaydVJwVWBSXkRVtHUz7ohI73Tjtfd3g0F9zJF 3z/jlNDSL/2mC+BvmIrDgfdJWBSgYJ/3wqqvHcsqOpTgdsaUz3YDT58pfYhLOeacbTJ2 pi9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=JnUxOJIynAj3uI1y+sO3DfMh7ir+WlJGNb++LFrX210=; b=FA1D2mpMH4XkBbr6A9C273PpGhgMw9VkTbEQgLtCoVdcM5X16g4TXr9wvBcK+bGLUN sEJ7EEaTyk0mp1mabW2tVS0MOGvxB4cpxLQGA+7Pl4pPA6Ky79SGKy8ItkS64OD2dKc6 GSCe+aeo7KXmM84vSnWGm5589jUXjOGR4ZLOcKsNZwhv5DMVof+LQD2OX6doGVC3zCaO E9agoFbKTlc5w8CRJOYY1Rncle5JEApXzlZBL8gwyKhbgsi/yGgu9xKEk1yBAE/yq59b VQpKVa65VTpSSjtRBlJD7Tib2rRNUiDX5UUdpJLDNij2EGcuGD3DlFcv4WcasRtLrziQ 8f2Q== X-Gm-Message-State: AOAM530pfWeF030TNDhgOjAhYde4I36khvvJv6B73ps5KLC9rIIDJQ8u /OyIGKmX1N0BSztFgq1hJo+xAri/WKCP+NYF X-Google-Smtp-Source: ABdhPJwDJaLX/cxCmyUXAbVS/RQJ0TrA2KB4sujqSM5M2kIGaUl5fRFE83fHcKShMFNRZpNFvJCZuVmHOB0E6NxM Sender: "andreyknvl via sendgmr" X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:7220:84ff:fe09:7e9d]) (user=andreyknvl job=sendgmr) by 2002:a1c:1f05:: with SMTP id f5mr4382666wmf.98.1605305850004; Fri, 13 Nov 2020 14:17:30 -0800 (PST) Date: Fri, 13 Nov 2020 23:15:59 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.299.gdc1121823c-goog Subject: [PATCH mm v10 31/42] kasan, mm: untag page address in free_reserved_area From: Andrey Konovalov To: Andrew Morton Cc: Catalin Marinas , Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vincenzo Frascino free_reserved_area() memsets the pages belonging to a given memory area. As that memory hasn't been allocated via page_alloc, the KASAN tags that those pages have are 0x00. As the result the memset might result in a tag mismatch. Untag the address to avoid spurious faults. Cc: Andrew Morton Signed-off-by: Vincenzo Frascino Signed-off-by: Andrey Konovalov --- Change-Id: If12b4944383575b8bbd7d971decbd7f04be6748b --- mm/page_alloc.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 855627e52f81..4a69fef13ac7 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7653,6 +7653,11 @@ unsigned long free_reserved_area(void *start, void *end, int poison, const char * alias for the memset(). */ direct_map_addr = page_address(page); + /* + * Perform a kasan-unchecked memset() since this memory + * has not been initialized. + */ + direct_map_addr = kasan_reset_tag(direct_map_addr); if ((unsigned int)poison <= 0xFF) memset(direct_map_addr, poison, PAGE_SIZE); -- 2.29.2.299.gdc1121823c-goog