From nobody Thu Apr 16 00:56:40 2026 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 34CC0C4332F for ; Wed, 23 Nov 2022 01:15:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235304AbiKWBPt (ORCPT ); Tue, 22 Nov 2022 20:15:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235209AbiKWBPN (ORCPT ); Tue, 22 Nov 2022 20:15:13 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94BE0E2B53 for ; Tue, 22 Nov 2022 17:14:20 -0800 (PST) Received: from dggpeml500026.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NH36g6vcYzmW6X; Wed, 23 Nov 2022 09:13:47 +0800 (CST) Received: from huawei.com (10.175.101.6) by dggpeml500026.china.huawei.com (7.185.36.106) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 23 Nov 2022 09:14:18 +0800 From: Zhengchao Shao To: CC: , , , , , Subject: [PATCH] driver core: fix resource leak in device_add() Date: Wed, 23 Nov 2022 09:20:42 +0800 Message-ID: <20221123012042.335252-1-shaozhengchao@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500026.china.huawei.com (7.185.36.106) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When calling kobject_add() failed in device_add(), it will call cleanup_glue_dir() to free resource. But in kobject_add(), dev->kobj.parent has been set to NULL. This will cause resource leak. The process is as follows: device_add() get_device_parent() class_dir_create_and_add() kobject_add() //kobject_get() ... dev->kobj.parent =3D kobj; ... kobject_add() //failed, but set dev->kobj.parent =3D NULL ... glue_dir =3D get_glue_dir(dev) //glue_dir =3D NULL, and goto //"Error" label ... cleanup_glue_dir() //becaues glue_dir is NULL, not call //kobject_put() The preceding problem may cause insmod mac80211_hwsim.ko to failed. sysfs: cannot create duplicate filename '/devices/virtual/mac80211_hwsim' Call Trace: dump_stack_lvl+0x8e/0xd1 sysfs_warn_dup.cold+0x1c/0x29 sysfs_create_dir_ns+0x224/0x280 kobject_add_internal+0x2aa/0x880 kobject_add+0x135/0x1a0 get_device_parent+0x3d7/0x590 device_add+0x2aa/0x1cb0 device_create_groups_vargs+0x1eb/0x260 device_create+0xdc/0x110 mac80211_hwsim_new_radio+0x31e/0x4790 [mac80211_hwsim] init_mac80211_hwsim+0x48d/0x1000 [mac80211_hwsim] do_one_initcall+0x10f/0x630 do_init_module+0x19f/0x5e0 load_module+0x64b7/0x6eb0 __do_sys_finit_module+0x140/0x200 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 kobject_add_internal failed for mac80211_hwsim with -EEXIST, don't try to register things with the same name in the same directory. Fixes: cebf8fd16900 ("driver core: fix race between creating/querying glue = dir and its cleanup") Signed-off-by: Zhengchao Shao --- drivers/base/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index d02501933467..1a7e74840dad 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3451,7 +3451,7 @@ int device_add(struct device *dev) /* we require the name to be set before, and pass NULL */ error =3D kobject_add(&dev->kobj, dev->kobj.parent, NULL); if (error) { - glue_dir =3D get_glue_dir(dev); + glue_dir =3D kobj; goto Error; } =20 --=20 2.17.1