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=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 504A1C4742C for ; Tue, 10 Nov 2020 22:12:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D03A20674 for ; Tue, 10 Nov 2020 22:12:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="iJj1JmG/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732896AbgKJWM3 (ORCPT ); Tue, 10 Nov 2020 17:12:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48548 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732876AbgKJWM0 (ORCPT ); Tue, 10 Nov 2020 17:12:26 -0500 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 716D6C0613D3 for ; Tue, 10 Nov 2020 14:12:26 -0800 (PST) Received: by mail-qk1-x749.google.com with SMTP id u16so165795qkm.22 for ; Tue, 10 Nov 2020 14:12:26 -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=l253EjoD9wZWKjcMl+HZL7Y/RWdoQT2M7P8mMLYHCko=; b=iJj1JmG/+/LGQYBNxNKzKQSzUcZ/JvHFynshxI+fvd2EdRizy6Qruvz5HpH1X+pS2s LmwzJtSEuxZdNM7E2Nh5KEEPhIUj0FyXndlJuLIyOmLIMLeKdsSwkG1Ct+kgofaJE2mE LkVwEUc0Kkd1419uEP7R6z+ZVqVv0rJnF59wCeuOwXWdzBVUoLHnajXG92tvPzyD3K0S Oo7dS5WPI9J3BbjlgBgEidOIyQbj6780q3v4oMiKj3CA3JSuCe1SQRDACZorbENHyR/m 233ANeiPkEhvGx/q1i/g7j4xUA2tRRuVUGpwN1JL+ziEL/Qu/TvjT58cy3lJpe58JfLH /zsg== 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=l253EjoD9wZWKjcMl+HZL7Y/RWdoQT2M7P8mMLYHCko=; b=faX3OTaYoOIRjkHwFys0+0BgZGS1qxc1bVOxkDXnVlndXPRitMzbQlF8u3kNwL5Qk0 HC0pCvq5cON324ewXTNKZgxXhepD/kZUkVgHcgzWz/UVzk8ACG87Ls32wKDTfAPUOy2L OUpikA9pCtYN97+OYGTzhdQrzdC3Hndlj2QTTASAgzyEO2EXAY3MJMPONmvDbVT9SXEN nHhFYR5kvIE7R12KHABz8yJxdL5rT9olFjB5JVQuuvkHWvSdSP+QSPPytQWGh43ccmTQ FN5kiO+Al2EZ+Hk57v9eHSYT5aITJt2TXuGUCo/oG1EmgRTIQ423DuyHc7rQpiVrNcrL KVsQ== X-Gm-Message-State: AOAM532NPmAlTNw3xJUgdPMimC3toOFjDQ6ulaldXFggQiqO2wCrGtwD c1CO0jPw5nboi3bdj5X7cEBX9PyHGknv1jdX X-Google-Smtp-Source: ABdhPJxokFbxfHNUyx6ne+LPZby1L6L3HSAB4pfI6nXjJC22jzllXP35wpy1FIYaxIucTW79eSxVCqU7onN0ujaX 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:a0c:aa8f:: with SMTP id f15mr20403403qvb.46.1605046345539; Tue, 10 Nov 2020 14:12:25 -0800 (PST) Date: Tue, 10 Nov 2020 23:10:30 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.222.g5d2a92d10f8-goog Subject: [PATCH v9 33/44] kasan, mm: untag page address in free_reserved_area From: Andrey Konovalov To: Catalin Marinas Cc: Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , Andrew Morton , 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 23f5066bd4a5..24b45261e2bd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7593,6 +7593,11 @@ 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); -- 2.29.2.222.g5d2a92d10f8-goog