From patchwork Wed Nov 15 20:30:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ilya Leoshkevich X-Patchwork-Id: 13457323 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="emT9maAc" Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 954CA1991; Wed, 15 Nov 2023 12:34:55 -0800 (PST) Received: from pps.filterd (m0353724.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3AFKSANo032237; Wed, 15 Nov 2023 20:34:40 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=CK3CSFhKHiUxb3M2GZk8QRFPFYlA6+i6yOOL0Bh28Bg=; b=emT9maAcJzRM0G1DzNyB9iM8ZDVH2esBnEg/GihJ7LhUH2LLr25n4T16fwdyJps5Swbk wi4ydQ4vQY1dt3LHU3iEbPpDRQlK2WN3UgmbbuFpWQqA+NdbB1X1DTRjZDb79cxWxs14 l92PTve6gZdcBi+zTfFpznNCncAP5bY1O8MJRp6g0ZKo+7YKzVTEB37DAfMRevUc1q+d +eknBIA7PwtuOwMk5F3TMX2Uxm634QiwPtiNOYXcOzTFrM4zQMZuFhT8+4ha9MGLnPSb 339/RbJXkgFBm6wWvggkH1xF3nzhdx7IKq75wA+RnlnWIvdnE3fRnpaZkzLi2MevaFfd tw== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3ud4v38cv2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Nov 2023 20:34:40 +0000 Received: from m0353724.ppops.net (m0353724.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 3AFKG6nw003579; Wed, 15 Nov 2023 20:34:40 GMT Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3ud4v38cur-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Nov 2023 20:34:39 +0000 Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 3AFKJ1FS017525; Wed, 15 Nov 2023 20:34:39 GMT Received: from smtprelay02.fra02v.mail.ibm.com ([9.218.2.226]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3uamayj7ap-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 15 Nov 2023 20:34:39 +0000 Received: from smtpav01.fra02v.mail.ibm.com (smtpav01.fra02v.mail.ibm.com [10.20.54.100]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 3AFKYaAX24576754 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Nov 2023 20:34:36 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 00EC32004E; Wed, 15 Nov 2023 20:34:36 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AB2F120040; Wed, 15 Nov 2023 20:34:34 +0000 (GMT) Received: from heavy.boeblingen.de.ibm.com (unknown [9.179.9.51]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 15 Nov 2023 20:34:34 +0000 (GMT) From: Ilya Leoshkevich To: Alexander Gordeev , Alexander Potapenko , Andrew Morton , Christoph Lameter , David Rientjes , Joonsoo Kim , Marco Elver , Masami Hiramatsu , Pekka Enberg , Steven Rostedt , Vasily Gorbik , Vlastimil Babka Cc: Christian Borntraeger , Dmitry Vyukov , Hyeonggon Yoo <42.hyeyoo@gmail.com>, kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Mark Rutland , Roman Gushchin , Sven Schnelle , Ilya Leoshkevich Subject: [PATCH 16/32] mm: kfence: Disable KMSAN when checking the canary Date: Wed, 15 Nov 2023 21:30:48 +0100 Message-ID: <20231115203401.2495875-17-iii@linux.ibm.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231115203401.2495875-1-iii@linux.ibm.com> References: <20231115203401.2495875-1-iii@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: A7EFZ5gScxsCuOEPrsIMx7XtWnrv7KuJ X-Proofpoint-ORIG-GUID: bCKwaI7qewBSCpfDoKVTIbT55i3gylk2 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.987,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-11-15_20,2023-11-15_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 mlxscore=0 suspectscore=0 impostorscore=0 malwarescore=0 adultscore=0 spamscore=0 priorityscore=1501 lowpriorityscore=0 phishscore=0 bulkscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311060000 definitions=main-2311150163 KMSAN warns about check_canary() accessing the canary. The reason is that, even though set_canary() is properly instrumented and sets shadow, slub explicitly poisons the canary's address range afterwards. Unpoisoning the canary is not the right thing to do: only check_canary() is supposed to ever touch it. Instead, disable KMSAN checks around canary read accesses. Signed-off-by: Ilya Leoshkevich --- mm/kfence/core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 3872528d0963..a2ea8e5a1ad9 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -306,7 +306,7 @@ metadata_update_state(struct kfence_metadata *meta, enum kfence_object_state nex } /* Check canary byte at @addr. */ -static inline bool check_canary_byte(u8 *addr) +__no_kmsan_checks static inline bool check_canary_byte(u8 *addr) { struct kfence_metadata *meta; unsigned long flags; @@ -341,7 +341,8 @@ static inline void set_canary(const struct kfence_metadata *meta) *((u64 *)addr) = KFENCE_CANARY_PATTERN_U64; } -static inline void check_canary(const struct kfence_metadata *meta) +__no_kmsan_checks static inline void +check_canary(const struct kfence_metadata *meta) { const unsigned long pageaddr = ALIGN_DOWN(meta->addr, PAGE_SIZE); unsigned long addr = pageaddr;