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=-26.3 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,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 05BA7C8300E for ; Mon, 23 Nov 2020 20:10:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A12B420721 for ; Mon, 23 Nov 2020 20:10:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="vkxW6RZN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731541AbgKWUJq (ORCPT ); Mon, 23 Nov 2020 15:09:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731416AbgKWUJl (ORCPT ); Mon, 23 Nov 2020 15:09:41 -0500 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79B7EC061A4E for ; Mon, 23 Nov 2020 12:09:41 -0800 (PST) Received: by mail-qv1-xf4a.google.com with SMTP id m3so4114700qvw.5 for ; Mon, 23 Nov 2020 12:09:41 -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=JqOdOudIAs6fCsGoOMJBOXRAJ4nBM51Q9IuLvpe9X7o=; b=vkxW6RZNeiKt3uDXc9cHATR3yMNcOPJqStPkUehbC/zuvJcXUjcLUlqnCHiChMMXOM c71zmtYoiGl5xy8iIG7mT1M1VQucOQvK1LAC5ywznp2VK69TDjuYjE4jSsbKaRpiUm8y sM6M/LJaplFV13/x/OJvNqf/icVGsPo2tG/Lf+RwL6jkzxr7ofjAqqsanPWI677zjgYP lbRjaTr3RXJWAWEbSbifTQIYdzFOZ9607IvrKeoWsbPXMOJQyh/MOW++TV1RAnTyiBD0 rGAzeg91KocpdVKgKspqM96WumykTFfRxbnrlu4hk2QablCk2YfVGGBB8TQ2fNZAYkRT bJOw== 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=JqOdOudIAs6fCsGoOMJBOXRAJ4nBM51Q9IuLvpe9X7o=; b=J921//56Vnr0OECNayinQyWXQCD6PB1+S37gQrjDxce0zbqUMOGuqmdfvKZ5SgksGI gLvnARULuAEVdsVFQBCUlG0Ieg0RT78AURsQ6HYaSe5Sy2h5Y4Hw8DfdackorO3FNiPZ vhGIVXHvsXo6MwExgEMoGR1NPXdimIjarQibkLf1Wb3bNtysBkXWoRyFGpAjYBtyaEj7 z2otU3RzGYdb0jrrz+ulxWFqjs7fMMxHJVwiiCTK9Mp9lzViJJqB0b1CU8VpdKLegZb8 xDPbvD/50MYwj1el8T0UI1LBN8XvyXxzU7Nt/RBZMakw/eIpVYcBj/p+w6kFnVlxjN1a Calg== X-Gm-Message-State: AOAM533PRNcxotO2gxh0pAs0LD0QFUQa6FAEpd6WT0C82rNProxGdmWF C9us/nGXJQ5GrAmXKwsmPHRhVvUqwUt50bsX X-Google-Smtp-Source: ABdhPJw73/jwZg0RlewlvU4441kNk0gTp+b0T2ipYrKP6rHNENxFPnemmxMhgs3u5M7bN/vqoeTq/VUwN6Xwbz1I 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:a05:6214:a8f:: with SMTP id ev15mr1201051qvb.20.1606162180614; Mon, 23 Nov 2020 12:09:40 -0800 (PST) Date: Mon, 23 Nov 2020 21:07:55 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog Subject: [PATCH mm v11 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 Reviewed-by: Alexander Potapenko --- 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 42c32e8a9c5d..236aa4b6b2cc 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7659,6 +7659,11 @@ 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); -- 2.29.2.454.gaff20da3a2-goog