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Content-Language: en-US To: Kui-Feng Lee , bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org, kernel-team@meta.com, song@kernel.org Cc: Nathan Slingerland References: <20221216015912.991616-1-kuifeng@meta.com> <20221216015912.991616-2-kuifeng@meta.com> From: Yonghong Song In-Reply-To: <20221216015912.991616-2-kuifeng@meta.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SJ0PR05CA0185.namprd05.prod.outlook.com (2603:10b6:a03:330::10) To SN6PR1501MB2064.namprd15.prod.outlook.com (2603:10b6:805:d::27) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SN6PR1501MB2064:EE_|BN6PR15MB1537:EE_ X-MS-Office365-Filtering-Correlation-Id: 9b4ff4be-0cc3-4fff-67ab-08dadf991535 X-FB-Source: Internal 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:SN6PR1501MB2064.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(136003)(396003)(376002)(346002)(366004)(39860400002)(451199015)(31686004)(2906002)(5660300002)(4744005)(8936002)(316002)(8676002)(41300700001)(66556008)(31696002)(66476007)(66946007)(36756003)(6486002)(4326008)(107886003)(6512007)(478600001)(53546011)(6506007)(186003)(2616005)(86362001)(38100700002)(83380400001)(45980500001)(43740500002);DIR:OUT;SFP:1102; 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however, the death of a task will clear the pointer, > even though we still hold the task_struct. That can cause an > unexpected crash for a null pointer when an iterator is visiting a > task that dies during the visit. Keeping a reference of mm on the > iterator ensures we always have a valid pointer to mm. > > Co-developed-by: Song Liu > Signed-off-by: Song Liu > Signed-off-by: Kui-Feng Lee > Reported-by: Nathan Slingerland Acked-by: Yonghong Song