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Fri, 11 Mar 2022 11:11:31 +0000 Date: Fri, 11 Mar 2022 14:11:20 +0300 From: Dan Carpenter To: Haowen Bai Cc: Larry.Finger@lwfinger.net, phil@philpotter.co.uk, gregkh@linuxfoundation.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] staging: r8188eu: simplify unnecessary NULL check Message-ID: <20220311111120.GJ3293@kadam> References: <1646994801-26211-1-git-send-email-baihaowen@meizu.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1646994801-26211-1-git-send-email-baihaowen@meizu.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-ClientProxiedBy: MR2P264CA0034.FRAP264.PROD.OUTLOOK.COM (2603:10a6:500::22) To MWHPR1001MB2365.namprd10.prod.outlook.com (2603:10b6:301:2d::28) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 153d0013-209e-4a7a-e5a8-08da034fe581 X-MS-TrafficTypeDiagnostic: DM6PR10MB4220:EE_ X-Microsoft-Antispam-PRVS: X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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> free_adapter: > if (status != _SUCCESS) { > - if (pnetdev) > - rtw_free_netdev(pnetdev); > - else if (padapter) > - vfree(padapter); > + rtw_free_netdev(pnetdev); > + vfree(padapter); The rtw_free_netdev() frees padapter so this patch would introduce a double free. This driver is kind of garbage so I don't really fault you for making this mistake. If the error handling and cleanup were written in the correct way it would avoid accidentally creating bugs like this: https://lore.kernel.org/all/20210831084735.GL12231@kadam/ The correct thing is to not call rtw_free_netdev() from rtw_usb_if1_init() but to instead call: free_netdev: free_netdev(pnetdev); handle_dualmac: rtw_handle_dualmac(padapter, 0); free_padapter: vfree(padapter); Also you need to work against the latest linux-next or staging-next tree. regards, dan carpenter