From nobody Tue Apr 7 12:19:45 2026 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 603B1ECAAD4 for ; Mon, 29 Aug 2022 07:56:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229746AbiH2H4G (ORCPT ); Mon, 29 Aug 2022 03:56:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229725AbiH2Hz4 (ORCPT ); Mon, 29 Aug 2022 03:55:56 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B63F82715A for ; Mon, 29 Aug 2022 00:55:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1661759755; x=1693295755; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=jcnnNskazsBc3DHIiMPQsDf7lUlURK3M021eCeUP7pM=; b=OGcIyYRbXBOQQejgaaDTfoCuJJSngme/mry8Wzwg/caju5n9W3z8SguK X7zDPFtNKj+wftSQH3It4wQagJD3WbIAQwNvz40prKQo7eSiZ/oKxD8/D L96PWpwjYsISi3JsHbfpdYWKkD461oAO/Wps+oCtOm/YHPan+3miV/r6p GJGkOOhqO9lKqtzm0GnO2GTu7pllHRZFui8GS0+BcqhLiqjh8y/E/ZvT0 AiEPqvIC8iQo6nvQYxCxfZxLI3b7iD+BUIuhS0hxj7WFmDFAuaokTiugp 8UpXqz6mMl+KrKndQ6P2eNkHb+uxmGeEWGVBD1I5IX0V1pXLWFeSSe5fp Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10453"; a="381140133" X-IronPort-AV: E=Sophos;i="5.93,272,1654585200"; d="scan'208";a="381140133" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2022 00:55:55 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,272,1654585200"; d="scan'208";a="672283586" Received: from shbuild999.sh.intel.com ([10.239.147.181]) by fmsmga008.fm.intel.com with ESMTP; 29 Aug 2022 00:55:52 -0700 From: Feng Tang To: Andrew Morton , Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Dmitry Vyukov Cc: Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Feng Tang , kernel test robot Subject: [PATCH v4 3/4] mm: kasan: Add free_meta size info in struct kasan_cache Date: Mon, 29 Aug 2022 15:56:17 +0800 Message-Id: <20220829075618.69069-4-feng.tang@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20220829075618.69069-1-feng.tang@intel.com> References: <20220829075618.69069-1-feng.tang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When kasan is enabled for slab/slub, it may save kasan' free_meta data in the former part of slab object data area in slab object free path, which works fine. There is ongoing effort to extend slub's debug function which will redzone the latter part of kmalloc object area, and when both of the debug are enabled, there is possible conflict, especially when the kmalloc object has small size, as caught by 0Day bot [1] For better information for slab/slub, add free_meta's data size info 'kasan_cache', so that its users can take right action to avoid data conflict. [1]. https://lore.kernel.org/lkml/YuYm3dWwpZwH58Hu@xsang-OptiPlex-9020/ Reported-by: kernel test robot Signed-off-by: Feng Tang Acked-by: Dmitry Vyukov --- include/linux/kasan.h | 2 ++ mm/kasan/common.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/include/linux/kasan.h b/include/linux/kasan.h index b092277bf48d..293bdaa0ba09 100644 --- a/include/linux/kasan.h +++ b/include/linux/kasan.h @@ -100,6 +100,8 @@ static inline bool kasan_has_integrated_init(void) struct kasan_cache { int alloc_meta_offset; int free_meta_offset; + /* size of free_meta data saved in object's data area */ + int free_meta_size_in_object; bool is_kmalloc; }; =20 diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 69f583855c8b..762ae7a7793e 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -201,6 +201,8 @@ void __kasan_cache_create(struct kmem_cache *cache, uns= igned int *size, cache->kasan_info.free_meta_offset =3D KASAN_NO_FREE_META; *size =3D ok_size; } + } else { + cache->kasan_info.free_meta_size_in_object =3D sizeof(struct kasan_free_= meta); } =20 /* Calculate size with optimal redzone. */ --=20 2.34.1