Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 7 Jul 2023 11:18:47 -0400
From:   "Liam R. Howlett" <Liam.Howlett@Oracle.com>
To:     Peng Zhang <zhangpeng.00@bytedance.com>
Cc:     akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, maple-tree@lists.infradead.org
Subject: Re: [RESEND PATCH 4/8] maple_tree: fix mas_validate_child_slot() to
 check last missed slot
Message-ID: <20230707151847.xzhnismksfdf7ye2@revolver>
Mail-Followup-To: "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
        Peng Zhang <zhangpeng.00@bytedance.com>, akpm@linux-foundation.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        maple-tree@lists.infradead.org
References: <20230707101057.29326-1-zhangpeng.00@bytedance.com>
 <20230707101057.29326-5-zhangpeng.00@bytedance.com>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230707101057.29326-5-zhangpeng.00@bytedance.com>
User-Agent: NeoMutt/20220429
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?LszjcQowFRTVwyfIAHgFVJLwZLLrcShTVPcQQ/BawJSl1n+HdepGbXgif1Hn?=
 =?us-ascii?Q?XQWARyJax22v8EUo3yhhU1YiGAv1SxFtJUlfC2Qw6pKHUhgDQICHNzkNTwmV?=
 =?us-ascii?Q?o+Ip3brSvqa+pv01w41lkUqQ5jMvMZ0LXvNygovOde7/zdipdOSYfeBOlY/r?=
 =?us-ascii?Q?aCwNQNycmHwp4uWQo10rhkHzS9OSJB4H3i4s5RC730dBN3cNGbBVG0mWzCL6?=
 =?us-ascii?Q?u3xktIfbJblcw8iKtRNq2VOfXZNy4TIG+S2WsKip/Z3WbgV5ZF/imKsI9z8i?=
 =?us-ascii?Q?SkH4RKrPJBshMuyLYrHAKQZC6XhA1Jo6WDRZY0pCPGvG3nxYJPqPWNsKuOP7?=
 =?us-ascii?Q?5zdJ2M8Fh/AG69/mKXy+PcacYqUPPnmNrPwDbtPtOxAOUy9UxElmGq8vHLd5?=
 =?us-ascii?Q?ppc0KHDdd1iyw3Dwj1a8gvcXzcRMBnDHYW1HpT/nFNrBbuwkn8B8p2FAuJeb?=
 =?us-ascii?Q?8rBX2KyCNAbMsW9jdNYL0QV1VTCm5NtBPDs5QtwMpXVWI4IQa6G1bZF8Az3l?=
 =?us-ascii?Q?e5L4urdyqPCc3akgtAiV41D9y+J8CTJ/K2f/vaJaxtlHM1Bo2hzNfhblCkFB?=
 =?us-ascii?Q?abwdojGP/5SQeI7/C6epPhuaMXSDHkBa+qk/mQfUAQgRcsCh3NofWwhIVpJk?=
 =?us-ascii?Q?IjPYMCW3bScpoeHDlxzM9YegYlRzqBSLlnbN2HodebJrjYQ/wgcw7jhz/k0Q?=
 =?us-ascii?Q?z4znHvdV0udd19fmWrSEIgZDSFd5VYMA8qbHlUrTmiF0nJXOm1Mgax22jZgV?=
 =?us-ascii?Q?TebE2ldrmiqq8YjtrE+gcXlvtu6bBIqRiluO/HqB3WXg0BTeSsm2hYxuHp+w?=
 =?us-ascii?Q?DihILvCJZ0xA83xoTpXBlipHgPAzuiV0CdJjckylY9IpIPaNd8dlvjYsxDEF?=
 =?us-ascii?Q?1fDIwOk6vxEVbghhqbeYbqvJ9SD8a2Ukh7pPIA1DnW8ZIbw99dMP9NGk4dRk?=
 =?us-ascii?Q?PfMgOpxBlo+wXVggxPIbanwbZHYwsWncWXZ3mvuPIlc2Tx7Rq4d3t9b2swz1?=
 =?us-ascii?Q?wDhq3QoMHwbfMt6NfPWLX2v5jcZrEb3SFutlKKWHab3mc4y43JQeWzO96mGZ?=
 =?us-ascii?Q?qwKbzuZ+soBA3PUVrKQ1WRI3iZhnDoyEhteMdCfLstDcv+BfQkM0NMOUN1lL?=
 =?us-ascii?Q?q9EDO27Q2o3UZ+Q7gLVrMlQkOutv7vZNT5wY8g2PToWuC/Jjpt8SxphHKjYQ?=
 =?us-ascii?Q?IW/dNXHHAS/W5cdEaxUOw1pd1MmpC3ZuwxGclWY9CfpGpoz/OBCPP4gREY7C?=
 =?us-ascii?Q?MrUIi5NQgMb63BQeEppMWvHfkosukVZaSY5xP1XjSLi3nLeyr9AqT6bnk0sp?=
 =?us-ascii?Q?e34d7W7Ahb10ixTAefA3MtwtDZ4Ne0fvMJyDK6VzAZ94dXkYh56E5cwXYwRi?=
 =?us-ascii?Q?hx6YQRHyItapsyLSP5OytfCVI7Gc+i5Hpwt4h7R6ZzKsOoooVWrD5Ee0xWHi?=
 =?us-ascii?Q?uDjRXDDRG0OFfNCzKY3ZsLwWoHaDBKfYNCdJ3vVvl/+D2KOQ/w8qnXGu8rg6?=
 =?us-ascii?Q?WWFKOLG4g0W/JsFFEMLepFrlBRqJZUwxw3idv30VLyF0ZdOjsh/rYpQUthcQ?=
 =?us-ascii?Q?OZt8WHD7YoSPPkeDmoT9S1Yxd1ut2pLJ490I4youu33ym4IGx4BH1MYkvZ8l?=
 =?us-ascii?Q?Gg=3D=3D?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: =?us-ascii?Q?31YnHtVCTkQaym/x3H7KdcQ06KnyriYXcZY/mJstUSJzCNHx9xkOGIIms8CN?=
 =?us-ascii?Q?kTpR097A4vAw+A4Wz5C89v3hTJlnMqjPjQAVIvVMtsJyPUN259OK3CYVkWb2?=
 =?us-ascii?Q?nfzvumWcMG8izYJCtk0zUfyQN5ycWxk8Qt0+Kcv6UM//Ma6lz1ykW5nAt2Ib?=
 =?us-ascii?Q?30jS7voYhV2EtPpc5GLKdSVyhlCTcDI8bUOvLnczvm+gnJp9eiykjvBzhqjB?=
 =?us-ascii?Q?HCCe1yYUSAx6eUqVxMg9SEGQ/6fLdra3bg4wtCh1Pw16dHTqBUsxKJ0uX0Mc?=
 =?us-ascii?Q?plguG8aoK8rqNIk5bCpcF65Z9729UP+ZhgxntlCceOB6N3rYZ7UcgGM39OkZ?=
 =?us-ascii?Q?H/bHqj1XvPth67kNnYTyup1ozZ/+8tutoxXDO8JDxCYRKs5nZMoFFz7Vy4j0?=
 =?us-ascii?Q?R7G21cnFWFaIRLqFPD5iwbl2fP8h2XD1fk0Sz0t2LRSzr7T8nKYdABsit9K+?=
 =?us-ascii?Q?3Q5jAYo4GkxKzuuf8lOTZPCIakoGw7UkVQ0tlSdy+m9punIA/2GBJ5D2ENeI?=
 =?us-ascii?Q?AUV1MkaJ6eWMr9D3Xlh+PGj9DBpo/Bd0auVHsRJ5LQX1hxf8hTx2VLTTl9f9?=
 =?us-ascii?Q?qqE3ZldF6rzcYf0IbknqzlkUR480bdN819iEm2/EwQ1IdIWQ9d4IXARCAcQV?=
 =?us-ascii?Q?9WssTd2NgypdAhuh/sKMujU+XppJ5t38zE0x8TpZ8Jfwdmr578BUr8qVyNN7?=
 =?us-ascii?Q?+gClD7PwV+ySPXFscR720GgFJpA344dkHWBxhMeQAvNCcLsAt2jbqEb0OkvM?=
 =?us-ascii?Q?NPi9Pw2wKkpog+qoZ+uZ6uDhnUg8GIcy2MGPJZMbMX0BP6d4HYz8c9Gf45c8?=
 =?us-ascii?Q?2u4sMaBbgYEQPaQxmTByQ5XcsDwBcYwAG5FENnPLZD9BQphpIixEjePf39Qi?=
 =?us-ascii?Q?utUyPDKzm6t80h60fFQ1TDck+gZpQW4r0wD7ymUda3Uf2Q39pocpfPhcnZFm?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 2b2f45ee-f1c2-4b29-6bfd-08db7efd77e0
X-MS-Exchange-CrossTenant-AuthSource: SN6PR10MB3022.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 07 Jul 2023 15:18:50.6968
 (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: yqqnrRhwJGsaNADIut4omQ5r2dWvd6bUQZQV/XMBYwpq6MTV2a7vEcxRRyed2ZfV3JMLcDZBUvOgx+ODGVoVHQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR10MB7330
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26
 definitions=2023-07-07_10,2023-07-06_02,2023-05-22_02
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0
 mlxlogscore=999 adultscore=0 bulkscore=0 suspectscore=0 spamscore=0
 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2305260000 definitions=main-2307070141
X-Proofpoint-ORIG-GUID: 2uZKZ-EfFZ-92tlStloyR9yQcCsjS-Bc
X-Proofpoint-GUID: 2uZKZ-EfFZ-92tlStloyR9yQcCsjS-Bc
X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,
        T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

* Peng Zhang <zhangpeng.00@bytedance.com> [230707 06:11]:
> Don't break the loop before checking the last slot. Also here check if
> non-leaf nodes are missing children.
> 
> Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>

Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>

> ---
>  lib/maple_tree.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 1fe8b6a787dd..88d6373f37b0 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -7111,11 +7111,12 @@ static void mas_validate_child_slot(struct ma_state *mas)
>  
>  	for (i = 0; i < mt_slots[type]; i++) {
>  		child = mas_slot(mas, slots, i);
> -		if (!pivots[i] || pivots[i] == mas->max)
> -			break;
>  
> -		if (!child)
> -			break;
> +		if (!child) {
> +			pr_err("Non-leaf node lacks child at %p[%u]\n",
> +			       mas_mn(mas), i);
> +			MT_BUG_ON(mas->tree, 1);
> +		}
>  
>  		if (mte_parent_slot(child) != i) {
>  			pr_err("Slot error at %p[%u]: child %p has pslot %u\n",
> @@ -7130,6 +7131,9 @@ static void mas_validate_child_slot(struct ma_state *mas)
>  			       mte_to_node(mas->node));
>  			MT_BUG_ON(mas->tree, 1);
>  		}
> +
> +		if (i < mt_pivots[type] && pivots[i] == mas->max)
> +			break;
>  	}
>  }
>  
> -- 
> 2.20.1
> 
>