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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2350EC6FA99 for ; Fri, 10 Mar 2023 19:14:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5539F8E0001; Fri, 10 Mar 2023 14:14:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 504686B0072; Fri, 10 Mar 2023 14:14:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 356148E0001; Fri, 10 Mar 2023 14:14:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 2291F6B0071 for ; Fri, 10 Mar 2023 14:14:21 -0500 (EST) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id E9712121201 for ; Fri, 10 Mar 2023 19:14:20 +0000 (UTC) X-FDA: 80553939480.20.DFA3252 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf17.hostedemail.com (Postfix) with ESMTP id 7D37540006 for ; Fri, 10 Mar 2023 19:14:17 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2022-7-12 header.b=fEGxQbdd; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=ChvwaKpu; spf=pass (imf17.hostedemail.com: domain of liam.howlett@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=liam.howlett@oracle.com; dmarc=pass (policy=none) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1678475657; a=rsa-sha256; cv=pass; b=7kGcgVTyOs2iiLUlCZ5XC1wSTaA/mNSWopg1CTyu/J7xl4gPQmQgFmHAXVVWNwZa4QjYvc 5ZR9fRO5QlZDlx3BJZaIDI7l4tzL6ZD2IdTUa5MrROVDez4PeX0ZJiXhGRgmu+mwt78oQH h6pUNF4kVu2AaQpkSqw+g7DIQkEC5Lw= ARC-Authentication-Results: i=2; imf17.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2022-7-12 header.b=fEGxQbdd; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=ChvwaKpu; spf=pass (imf17.hostedemail.com: domain of liam.howlett@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=liam.howlett@oracle.com; dmarc=pass (policy=none) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1678475657; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=PRt8lMqbN4KwnBC9JqXDz/DfhgdzgXGT7bZeFqX88WM=; b=58YgmWsSI0lY4BWXYcPJXUXrgsYwYz7dlL3w6/FOWucjqtEaJ8QkIcEdEHtX6BwiSp5roK UvF9Q6CAnDBSKQQ5GcKoE8PWxqXK1C+IOvC67c+P4YnLVOzM46HWib/tU0qlEUH/C6JEO3 dt8gL52YThksDj85hD0AqS3XpUTd0K8= Received: from pps.filterd (m0246627.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 32AF4ROn016561; Fri, 10 Mar 2023 18:27:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : content-type : in-reply-to : mime-version; s=corp-2022-7-12; bh=PRt8lMqbN4KwnBC9JqXDz/DfhgdzgXGT7bZeFqX88WM=; b=fEGxQbdd5/ar6jOtaz4Bm8rHyGq5WmEkdGpY2uStrCHCsnPKn1a99ZVxF0VsBC2m2eWj 6Dpgg+bsXUOKfkSFX3q+7ZxQOthpP1GJA41mbgQZSR/LzjYqSHA62RGu+aMDsKlf/aWg aU6mirLRtpvKM3qKGUkq2RMKObdtQXqT+fZx1lKeyQfYNDt2XcJ0sJRT9QnU85lBU88b hWpqVg3t3n3GaCWRffhf8OLTj8txMZhsmVCmS9GEsX3jxL80u8KOfnwfUhhb5aL/mrfZ zAyURs0dQnpGeCm6+o/cEq2TgPFJIE9+jN0O62RYNnv5Y2AnDM7nSChF7+wy4oxX6Ye8 wg== Received: from iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta01.appoci.oracle.com [130.35.100.223]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3p5nn9a87u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Mar 2023 18:27:23 +0000 Received: from pps.filterd (iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 32AHUXmX005146; Fri, 10 Mar 2023 18:27:22 GMT Received: from nam10-bn7-obe.outbound.protection.outlook.com (mail-bn7nam10lp2106.outbound.protection.outlook.com [104.47.70.106]) by iadpaimrmta01.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 3p6g4k17pd-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Mar 2023 18:27:22 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=TaIKjqroAnNB9Oge9pj1nrE0Ij41cBOqTwoRhuAQgKv9qqdNztJNvkz4PFwy1PpdTxvOzRMKjzKui76jkbZL80hDFqfCDcaDw1s5XlS/mak7PKkNTSBafPAtb+Ja+74MPkATY3GMpFlzC7+0kAbZo45o4kp4+UfHqfFzAFiO8ricvu/obIOBO01jq4V+P7osrbnDkSJNdvD8Bd/ZCWIuu4TrTtokZKlqWr0+qs3RmfkGyzWZs4unVNbinxzlP/UaAMSG9d+OV2iJUmlH2D8NPzrYewcep4gKxFBqwCiW27Ux9hdOZmWpffwjz8rWZDvS8J8FeDc8i2QVq0h+YnAtWw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=PRt8lMqbN4KwnBC9JqXDz/DfhgdzgXGT7bZeFqX88WM=; b=VcxZA9uUp66pVrlCdhm4sje+H4mGsBTQSjTVHhRRTvVKjRuqqZSedPC0IPbZgz1cKULAdzgwYSD4yMb6+EiALQMFpY4RrhR7SSc/j1h9eoRMgskCRtG42gqVQbsmqorP1EkQb9Zpk/wwT7LAw7OtTHMDVw+Xy4mcoU8UMZkM3BnD9TTavrczyeAHkHj+rbznYmZEdOuCL3F0ESRBw1RGHpLzYIwuSh2tqGU9uWW2AO3c/e46vGx4eEyCRTNKX4IGf6rIhPu3oQFuAwq96kqweVV8zFCIWfm/upQB5lQHkl8TQMnOHx+PvizgemAVkvw7jXNFIXmipsY+DAghp+auEg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=PRt8lMqbN4KwnBC9JqXDz/DfhgdzgXGT7bZeFqX88WM=; b=ChvwaKpuh0sK0ZFgApc6Tz+PZgJiHi+VDeWTY7NgB5T3A+OBMG2aorc/bUMHL0idAFBSHbzmm7+WmhbFMagTn+g8GGmYAtk2Vg9JWjoR1sEPfQ0fn5ixwxoU9CCpkbSAsgJ8ZnhvPldEuv/PJcSL+yu/GSVOzV3FrMUsgdaVsFY= Received: from SN6PR10MB3022.namprd10.prod.outlook.com (2603:10b6:805:d8::25) by MN2PR10MB4365.namprd10.prod.outlook.com (2603:10b6:208:199::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6178.19; Fri, 10 Mar 2023 18:27:21 +0000 Received: from SN6PR10MB3022.namprd10.prod.outlook.com ([fe80::93c9:c99e:5ab:4319]) by SN6PR10MB3022.namprd10.prod.outlook.com ([fe80::93c9:c99e:5ab:4319%7]) with mapi id 15.20.6178.019; Fri, 10 Mar 2023 18:27:20 +0000 Date: Fri, 10 Mar 2023 13:27:17 -0500 From: "Liam R. Howlett" To: Peng Zhang Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org Subject: Re: [PATCH 3/4] maple_tree: Fix a potential concurrency bug in RCU mode Message-ID: <20230310182717.csx4qgmvfvtc262c@revolver> Mail-Followup-To: "Liam R. Howlett" , Peng Zhang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org References: <20230310140848.94485-1-zhangpeng.00@bytedance.com> <20230310140848.94485-4-zhangpeng.00@bytedance.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230310140848.94485-4-zhangpeng.00@bytedance.com> User-Agent: NeoMutt/20220429 X-ClientProxiedBy: YT4PR01CA0159.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:ac::21) To SN6PR10MB3022.namprd10.prod.outlook.com (2603:10b6:805:d8::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN6PR10MB3022:EE_|MN2PR10MB4365:EE_ X-MS-Office365-Filtering-Correlation-Id: c790ae19-59d4-4d28-9b33-08db21951608 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN6PR10MB3022.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230025)(7916004)(39860400002)(396003)(346002)(136003)(366004)(376002)(451199018)(6486002)(186003)(86362001)(9686003)(38100700002)(316002)(33716001)(6506007)(83380400001)(26005)(1076003)(6512007)(66556008)(6666004)(2906002)(66476007)(41300700001)(5660300002)(478600001)(8936002)(6916009)(8676002)(66946007)(4326008);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?9VKiYyRM1C9/UjfLVLTJX2I2gLQAcLj47dFXEeavYEGbDkoikXwe2kdPd5Bw?= =?us-ascii?Q?XfsQ3WrTBgDGaYnySaMuDmVFWTYnAWR7cPTO21ZhYr7wwGmZnZCbUVkqj/ZG?= =?us-ascii?Q?5l87EaRV+/vsVsuIW4xnYTwSumWfPF0Pv13L5JEkHixMx70GYP2SwzSGZ3vf?= =?us-ascii?Q?6UIsZAlOC86QAHsmKaTLvkha0GlIfARyLh508NnbQYQnlnx9rXsCJDGygKeI?= =?us-ascii?Q?O1GZzINUDaHA40Gx3azASNRJIrXvniXAo3ha/QUReZLvY6MWSmjW9mmzwVV9?= =?us-ascii?Q?OTmuGSdTYBbj1dKAIsmUAV3JWvoSGs5MRby9C69qZFZz4RU3NlIkkXaG80OQ?= =?us-ascii?Q?mMB2VN4wmhShl2CKKapX2MaSMCzyDzwpupCeq1SEBnevfvNv/ObxpvoyQXMQ?= =?us-ascii?Q?q+wchz+b0Dm7K7j3GMQV21NRSU9A8VQlZ4/Q9ddUuwhWfYTctY0iWg7vqooh?= =?us-ascii?Q?UTeitc6AI1Ph62Zx1cx/oUmG9Hwm2kUXSQ6guhFSX1D0sgKoIYjIPkiDZuZv?= =?us-ascii?Q?oPZhDpIxKPudIX4gjBtA/6dTLiwVVcH5avGFzKPlZmHzCzL6863rgTjk1iRm?= =?us-ascii?Q?sU/mDVgDDfCvDNHOMJ/1qT6KP9yiNyAIL8TbZtzNNyKPVxy+TM+bQZEZGwOw?= =?us-ascii?Q?LVYxxaKvGvSjE1XHstqPmBXzWkKbhYSuwJJAtheGLg+30wswV3cFZZrWIKX3?= =?us-ascii?Q?57/SnlN8yKc3EwSR9I2+RuqUQhOap9jmPLBxwYTNzbwqfw+3gMPUhharDGTA?= =?us-ascii?Q?IFdNkzD7hkD9nIpK4exmpYAAV3fg1b5FT9sDlZr33FNSHwam7tQyXze6OhAD?= =?us-ascii?Q?+5LAz2Oew5zKrfi5VxDVWYfFQtURIRPYtDKVz1T0qDyvNIUkRGCM5VYPKi0L?= =?us-ascii?Q?THUNyUWauACK0WmdJndPV2UryqiSPTtnl+Yz7TEy29Zr3Lis2Lg7kUrP828M?= =?us-ascii?Q?YzxF7peyF1MbO2e5LtYat4hldBhP1ccMv3e7KU3lRItWheN0ImRZh1OW0bia?= =?us-ascii?Q?NKXRKNjVfuYftBxdWQZQoxnKeLsi43Jl7KFKPDMV/nAAKcnK+q251FpXp7BJ?= =?us-ascii?Q?Hr2lfvExIDgToZwQs9Mm8Ah9xT+IwT7/zLM4Ule5W/4U8AEKKd0pm3fP3a/E?= =?us-ascii?Q?Rd9H14vitgWJT+/Gyv0wOmDBp3dFYH043Sy51s0mGz30UNxDjCjrbzMdNH/A?= =?us-ascii?Q?emIhBwIXiay8dakau4I2jdA/xmm4t0m+IWExioRoyn9+X5LzYyoG87DnPCmV?= =?us-ascii?Q?XtWX9PRxmKpXeLUDXh7XBK52NUFmFWsRMXTrHOHDBB1GRNPoX60I81KuCyvw?= =?us-ascii?Q?Otar8HKB/qj4suxEZQQ0A37bONlZ8hCAdxzIXk5I5wFEDKY98B/zLtvE0n3z?= =?us-ascii?Q?5ukP3hZeiKw0/QKYFPJLTOcWME4RpCfB7autqL6uQScwBTEEIy3Vs/PQaJ30?= =?us-ascii?Q?o7QuzRlt34eKnNpJDnCB0tlVckKlgioDj4fvqtLybBZ9FBZtN9zrI/XAbUjd?= =?us-ascii?Q?TRwfiDSyFkv/Xctnd7Tea/0XnKafWgySpfBKJb7bjHLSy3vMN2UIvUcjLV/M?= =?us-ascii?Q?hFXRNSKtAEysLTDiTHFWmfrKn6Du6ZxaFTxhrcGkQnjwn05ncOjTbKDW1DCc?= =?us-ascii?Q?uA=3D=3D?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: c790ae19-59d4-4d28-9b33-08db21951608 X-MS-Exchange-CrossTenant-AuthSource: SN6PR10MB3022.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Mar 2023 18:27:20.7657 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: zy9nTlqvd9hiLjD70hAjKvEIqAwPfBVl21TcBKkVXXah7MrSX0vLyFDGQ9uqYXC4uFUcqGG0Y3CJtdEhB6CFfw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR10MB4365 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-03-10_09,2023-03-10_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 spamscore=0 mlxscore=0 mlxlogscore=952 adultscore=0 bulkscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2303100146 X-Proofpoint-GUID: 2EATcetvp6MBGMSWc3MzDjPaV_AMslFO X-Proofpoint-ORIG-GUID: 2EATcetvp6MBGMSWc3MzDjPaV_AMslFO X-Rspam-User: X-Rspamd-Queue-Id: 7D37540006 X-Rspamd-Server: rspam01 X-Stat-Signature: dwi537diyfhfhe5u5h9r8az7dejdryrs X-HE-Tag: 1678475657-834412 X-HE-Meta: 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 +6gyto/+ 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: * Peng Zhang [230310 09:09]: > There is a concurrency bug that may cause the wrong value to be loaded > when a CPU is modifying the maple tree. > > CPU1: > mtree_insert_range() > mas_insert() > mas_store_root() > ... > mas_root_expand() > ... > rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); > ma_set_meta(node, maple_leaf_64, 0, slot); <---IP > > CPU2: > mtree_load() > mtree_lookup_walk() > ma_data_end(); > > When CPU1 is about to execute the instruction pointed to by IP, > the ma_data_end() executed by CPU2 may return the wrong end position, > which will cause the value loaded by mtree_load() to be wrong. > > An example of triggering the bug: > > Add mdelay(100) between rcu_assign_pointer() and ma_set_meta() in > mas_root_expand(). > > static DEFINE_MTREE(tree); > int work(void *p) { > unsigned long val; > for (int i = 0 ; i< 30; ++i) { > val = (unsigned long)mtree_load(&tree, 8); > mdelay(5); > pr_info("%lu",val); > } > return 0; > } > > mt_init_flags(&tree, MT_FLAGS_USE_RCU); > mtree_insert(&tree, 0, (void*)12345, GFP_KERNEL); > run_thread(work) > mtree_insert(&tree, 1, (void*)56789, GFP_KERNEL); > > In RCU mode, mtree_load() should always return the value before or after > the data structure is modified, and in this example mtree_load(&tree, 8) > may return 56789 which is not expected, it should always return NULL. > Fix it by put ma_set_meta() before rcu_assign_pointer(). Are you able to write a test case for this issue? I understand it's a race so it may be difficult to catch. > > Signed-off-by: Peng Zhang Reviewed-by: Liam R. Howlett > --- > lib/maple_tree.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/lib/maple_tree.c b/lib/maple_tree.c > index 4d15202a0692..de43ff19da72 100644 > --- a/lib/maple_tree.c > +++ b/lib/maple_tree.c > @@ -3635,10 +3635,9 @@ static inline int mas_root_expand(struct ma_state *mas, void *entry) > slot++; > mas->depth = 1; > mas_set_height(mas); > - > + ma_set_meta(node, maple_leaf_64, 0, slot); > /* swap the new root into the tree */ > rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); > - ma_set_meta(node, maple_leaf_64, 0, slot); > return slot; > } > > -- > 2.20.1 >