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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 637A1C4332F for ; Wed, 9 Nov 2022 14:47:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229759AbiKIOrP (ORCPT ); Wed, 9 Nov 2022 09:47:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229640AbiKIOrO (ORCPT ); Wed, 9 Nov 2022 09:47:14 -0500 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F7131AF06 for ; Wed, 9 Nov 2022 06:47:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668005233; x=1699541233; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=cQV21dw08IX3jhsoT3sV2zJmVozb4uk7W7vYaEPvavI=; b=Y2vN8Hdi/gaW6dX//nBZrNe1Y5VscWg58XUKRIPe02d32pN5XFxMIsCr 930dKAmlD1dIqi7lIv9ftw8edVFU5dN3upEdjQuSYMhPuqlQPmrzDDhcx 0e8HqXz6CTSC9Si59Gg5Ozo8vBXQ18Jr+xWmJ9ahS4to+9//ukH2ejQa3 taXFpc+vnJm5n25wO4uMhabspYJXEdtub+tJWjCZWy6fwWCy+AFdh9rPX Mi4iuuRfSi6c1io9KWUg71KDyWx91tBEu+ouCUDNhK8rzDwnjXbyftDIX gH1v1qkPn1CagayuQQCyyq5jV+HqSkk5ZzeHZ+odRwvc/XCJk+ucZSDAj g==; X-IronPort-AV: E=McAfee;i="6500,9779,10525"; a="312792240" X-IronPort-AV: E=Sophos;i="5.96,150,1665471600"; d="scan'208";a="312792240" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Nov 2022 06:47:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10526"; a="742420858" X-IronPort-AV: E=Sophos;i="5.96,150,1665471600"; d="scan'208";a="742420858" Received: from smile.fi.intel.com ([10.237.72.54]) by fmsmga002.fm.intel.com with ESMTP; 09 Nov 2022 06:47:10 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.96) (envelope-from ) id 1osmM8-009mqQ-3A; Wed, 09 Nov 2022 16:47:08 +0200 Date: Wed, 9 Nov 2022 16:47:08 +0200 From: Andy Shevchenko To: Zeng Heng Cc: warthog618@gmail.com, linus.walleij@linaro.org, brgl@bgdev.pl, linux@roeck-us.net, linux-gpio@vger.kernel.org, liwei391@huawei.com, yuancan@huawei.com Subject: Re: [PATCH v2] gpiolib: fix memory leak in gpiochip_setup_dev Message-ID: References: <20221109093120.3128541-1-zengheng4@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221109093120.3128541-1-zengheng4@huawei.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Wed, Nov 09, 2022 at 05:31:20PM +0800, Zeng Heng wrote: > gcdev_register & gcdev_unregister call device_add & device_del to > request/release source. But in device_add, the dev->p allocated by > device_private_init is not released by device_del. First of all, we refer to the functions like func(). > So when calling gcdev_unregister to release gdev, it needs put_device > to release dev in the following. > > Otherwise, kmemleak would report memory leak such as below: > > unreferenced object 0xffff88810b406400 (size 512): > comm "python3", pid 1682, jiffies 4295346908 (age 24.090s) > hex dump (first 32 bytes): > 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... > ff ff ff ff ff ff ff ff a0 5e 23 90 ff ff ff ff .........^#..... > backtrace: Second, read Submitting Patches on how to provide your backtraces in the message body. > [<00000000a58ee5fe>] kmalloc_trace+0x22/0x110 > [<0000000045fe2058>] device_add+0xb34/0x1130 > [<00000000d778b45f>] cdev_device_add+0x83/0xe0 > [<0000000089f948ed>] gpiolib_cdev_register+0x73/0xa0 > [<00000000a3a8a316>] gpiochip_setup_dev+0x1c/0x70 > [<00000000787227b4>] gpiochip_add_data_with_key+0x10f6/0x1bf0 > [<000000009ac5742c>] devm_gpiochip_add_data_with_key+0x2e/0x80 > [<00000000bf2b23d9>] xra1403_probe+0x192/0x1b0 [gpio_xra1403] > [<000000005b5ef2d4>] spi_probe+0xe1/0x140 > [<000000002b26f6f1>] really_probe+0x17c/0x3f0 > [<00000000dd2dad9c>] __driver_probe_device+0xe3/0x170 > [<000000005ca60d2a>] device_driver_attach+0x34/0x80 > [<00000000e9db90db>] bind_store+0x10b/0x1a0 > [<00000000e2650f8a>] drv_attr_store+0x49/0x70 > [<0000000080a80b2b>] sysfs_kf_write+0x8c/0xb0 > [<00000000a28b45b9>] kernfs_fop_write_iter+0x216/0x2e0 > > unreferenced object 0xffff888100de9800 (size 512): > comm "python3", pid 264, jiffies 4294737615 (age 33.514s) > hex dump (first 32 bytes): > 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... > ff ff ff ff ff ff ff ff a0 5e 63 a1 ff ff ff ff .........^c..... > backtrace: > [<00000000bcc571d0>] kmalloc_trace+0x22/0x110 > [<00000000eeb06124>] device_add+0xb34/0x1130 > [<000000007e5cd2fd>] cdev_device_add+0x83/0xe0 > [<000000008f6bcd3a>] gpiolib_cdev_register+0x73/0xa0 > [<0000000012c93b24>] gpiochip_setup_dev+0x1c/0x70 > [<00000000a24b646a>] gpiochip_add_data_with_key+0x10f6/0x1bf0 > [<000000000c225212>] tpic2810_probe+0x16e/0x196 [gpio_tpic2810] > [<00000000b52d04ff>] i2c_device_probe+0x651/0x680 > [<0000000058d3ff6b>] really_probe+0x17c/0x3f0 > [<00000000586f43d3>] __driver_probe_device+0xe3/0x170 > [<000000003f428602>] device_driver_attach+0x34/0x80 > [<0000000040e91a1b>] bind_store+0x10b/0x1a0 > [<00000000c1d990b9>] drv_attr_store+0x49/0x70 > [<00000000a23bfc22>] sysfs_kf_write+0x8c/0xb0 > [<00000000064e6572>] kernfs_fop_write_iter+0x216/0x2e0 > [<00000000026ce093>] vfs_write+0x658/0x810 > > Because at the point of gpiochip_setup_dev here, where dev.release > does not set yet, calling put_device would cause the warning of > no release function and double-free in the following fault handler > route (when kfree dev_name). So directly calling kfree to release > dev->p here in case of memory leak. ... > @@ -539,6 +539,7 @@ static int gpiochip_setup_dev(struct gpio_device *gdev) > > err_remove_device: > gcdev_unregister(gdev); > + kfree(gdev->dev.p); > return ret; Third, I do not believe it's a correct fix. Have you read comments around device_del() / etc.? NAK. -- With Best Regards, Andy Shevchenko