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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 023EDCD13DA for ; Mon, 18 Sep 2023 07:26:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240104AbjIRH0b (ORCPT ); Mon, 18 Sep 2023 03:26:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240075AbjIRH0A (ORCPT ); Mon, 18 Sep 2023 03:26:00 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01A6DE6 for ; Mon, 18 Sep 2023 00:25:50 -0700 (PDT) X-UUID: 961e5f3e55f411eea33bb35ae8d461a2-20230918 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=pmAQXDi1eFJFIz1BbU82J1+CnIbylJEmn229iHCJQIs=; b=iXQBjyY+RHy3WfgWsRoEQk9ClNi24G+J9sMkQbBwomqELi5Sc59HCFnuCrY217QGTtK0HQtbfE2ZrXZVrjcGPKrqVwRspTafgyhE/84ceszmRUVXQszV2++LCssmXe375Mw790g8n6d5VhcdE3VSrLbuNxPhzjxz7qbi4x7e9/4=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.31,REQID:7d7382ba-4a4a-4e4a-9eb9-67af55be4359,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:0ad78a4,CLOUDID:31a6f5be-14cc-44ca-b657-2d2783296e72,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:817|102,TC:nil,Content:0|-5,EDM:-3,I P:nil,URL:0,File:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1, SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0 X-CID-BVR: 1,FCT|NGT X-CID-BAS: 1,FCT|NGT,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-UUID: 961e5f3e55f411eea33bb35ae8d461a2-20230918 Received: from mtkmbs11n1.mediatek.inc [(172.21.101.185)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1752200225; Mon, 18 Sep 2023 15:25:47 +0800 Received: from mtkmbs11n1.mediatek.inc (172.21.101.186) by mtkmbs13n1.mediatek.inc (172.21.101.193) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Mon, 18 Sep 2023 15:25:46 +0800 Received: from mszsdtlt102.gcn.mediatek.inc (10.16.4.142) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Mon, 18 Sep 2023 15:25:45 +0800 From: Haibo Li To: CC: , , , , , , , , , , , , , , , Subject: Re: [PATCH] kasan:fix access invalid shadow address when input is illegal Date: Mon, 18 Sep 2023 15:25:45 +0800 Message-ID: <20230918072545.87653-1-haibo.li@mediatek.com> X-Mailer: git-send-email 2.34.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Fri, Sep 15, 2023 at 4:46 AM 'Haibo Li' via kasan-dev > wrote: > > > > The patch checks each shadow address,so it introduces extra overhead. > > Ack. Could still be fine, depends on the overhead. > I do a simple test by reading memory. Read 4096 memory by loop and the reading unit is 8 bytes. __hwasan_load8_noabort is called 512(4096/8) times. Measure the time of memory read. Here is the result on ARM CA7X(repeat 100 times): ---------------min-------max-----avg---- before patch | 77.3ms | 80.6ms | 79.2ms| after patch | 77.2ms | 80.7ms | 79.2ms| ---------------------------------------- There is no obvious drop in this scenario. It may differ in different arch. just for information if you are intrested in it. > But if the message printed by kasan_non_canonical_hook is good enough > for your use case, I would rather stick to that.