From patchwork Wed Nov 9 09:31:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zeng Heng X-Patchwork-Id: 623124 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 01ACBC43219 for ; Wed, 9 Nov 2022 09:32:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230351AbiKIJcr (ORCPT ); Wed, 9 Nov 2022 04:32:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230338AbiKIJcp (ORCPT ); Wed, 9 Nov 2022 04:32:45 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F51722BEE for ; Wed, 9 Nov 2022 01:32:43 -0800 (PST) Received: from kwepemi500024.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4N6frc3SvyzRp1r; Wed, 9 Nov 2022 17:32:32 +0800 (CST) Received: from huawei.com (10.175.103.91) by kwepemi500024.china.huawei.com (7.221.188.100) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 9 Nov 2022 17:32:41 +0800 From: Zeng Heng To: , , , CC: , , Subject: [PATCH v2] gpiolib: fix memory leak in gpiochip_setup_dev Date: Wed, 9 Nov 2022 17:31:20 +0800 Message-ID: <20221109093120.3128541-1-zengheng4@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-Originating-IP: [10.175.103.91] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemi500024.china.huawei.com (7.221.188.100) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org 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. 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: [<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. Fixes: 159f3cd92f17 ("gpiolib: Defer gpio device setup until after gpiolib initialization") Signed-off-by: Zeng Heng --- changes in v2: - correct fix tag --- drivers/gpio/gpiolib.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 4756ea08894f..fa659af86d07 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -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; }