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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 72C25C47088 for ; Wed, 26 May 2021 20:08:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8F7D361378 for ; Wed, 26 May 2021 20:07:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F7D361378 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57874 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1llzos-00048J-Hx for qemu-devel@archiver.kernel.org; Wed, 26 May 2021 16:07:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50844) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1llziA-00005V-11 for qemu-devel@nongnu.org; Wed, 26 May 2021 16:01:02 -0400 Received: from indium.canonical.com ([91.189.90.7]:59644) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1llzi7-0008E4-KE for qemu-devel@nongnu.org; Wed, 26 May 2021 16:01:01 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.93 #5 (Debian)) id 1llzi2-0000zu-Pn for ; Wed, 26 May 2021 20:00:55 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id BCB472E81C7 for ; Wed, 26 May 2021 20:00:49 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 26 May 2021 19:55:12 -0000 From: Vitaly Buka <1921948@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Confirmed; importance=Undecided; assignee=rth@twiddle.net; X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: ajbennee pcc-goog pmaydell rth vitalybuka xairy X-Launchpad-Bug-Reporter: Andrey Konovalov (xairy) X-Launchpad-Bug-Modifier: Vitaly Buka (vitalybuka) References: <161713286145.25906.15042270704525675392.malonedeb@wampee.canonical.com> Message-Id: <162205891246.28081.5011885479556084942.malone@soybean.canonical.com> Subject: [Bug 1921948] Re: MTE tags not checked properly for unaligned accesses at EL1 X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="802ed26817d1cdd050553dbe99cc8a3cad1a3bc7"; Instance="production" X-Launchpad-Hash: 688d8389a45e1582a783f90622b566c2a1e345c4 Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.248, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1921948 <1921948@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" I see something similar in memset It SEGV on stur q0, [x4, #-16] = for x4 set to 0xd000055214fe008 and near tags are 0xd000055214fdff0 and 0xd000055214fe000 -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1921948 Title: MTE tags not checked properly for unaligned accesses at EL1 Status in QEMU: Confirmed Bug description: For kernel memory accesses that span across two memory granules, QEMU's MTE implementation only checks the tag of the first granule but not of the second one. To reproduce this, build the Linux kernel with CONFIG_KASAN_HW_TAGS enabled, apply the patch below, and boot the kernel: diff --git a/sound/last.c b/sound/last.c index f0bb98780e70..04745cb30b74 100644 --- a/sound/last.c +++ b/sound/last.c @@ -5,12 +5,18 @@ */ = #include +#include #include = static int __init alsa_sound_last_init(void) { struct snd_card *card; int idx, ok =3D 0; + + char *ptr =3D kmalloc(128, GFP_KERNEL); + pr_err("KASAN report should follow:\n"); + *(volatile unsigned long *)(ptr + 124); + kfree(ptr); = printk(KERN_INFO "ALSA device list:\n"); for (idx =3D 0; idx < SNDRV_CARDS; idx++) { KASAN tags the 128 allocated bytes with the same tag as the returned pointer. The memory granule that follows the 128 allocated bytes has a different tag (with 1/15 probability). Expected result: a tag fault is detected and a KASAN report is printed wh= en accessing bytes [124, 130). Observed result: no tag fault is detected and no KASAN report is printed. Here are the flags that I use to run QEMU if they matter: qemu-system-aarch64 -s -machine virt,mte=3Don -cpu max -m 2G -smp 2 -net user,host=3D10.0.2.10,hostfwd=3Dtcp:127.0.0.1:10021-:22 -net nic -nographic -kernel ./Image -append "console=3DttyAMA0 root=3D/dev/vda earlyprintk=3Dserial" -drive file=3D./fs.img,format=3Draw,if=3Dvirtio -no- shutdown -no-reboot To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1921948/+subscriptions