From nobody Thu Sep 18 21:42:40 2025 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 C4C59C3A5A7 for ; Fri, 2 Dec 2022 03:04:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231881AbiLBDEv (ORCPT ); Thu, 1 Dec 2022 22:04:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230163AbiLBDEt (ORCPT ); Thu, 1 Dec 2022 22:04:49 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3FFFD7572; Thu, 1 Dec 2022 19:04:47 -0800 (PST) Received: from dggpemm500007.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NNd3s2W5mzqSYQ; Fri, 2 Dec 2022 11:00:41 +0800 (CST) Received: from huawei.com (10.175.103.91) by dggpemm500007.china.huawei.com (7.185.36.183) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 2 Dec 2022 11:04:45 +0800 From: Yang Yingliang To: , CC: , , , , , Subject: [PATCH resend] chardev: fix error handling in cdev_device_add() Date: Fri, 2 Dec 2022 11:02:37 +0800 Message-ID: <20221202030237.520280-1-yangyingliang@huawei.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.103.91] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm500007.china.huawei.com (7.185.36.183) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" While doing fault injection test, I got the following report: ------------[ cut here ]------------ kobject: '(null)' (0000000039956980): is not initialized, yet kobject_put()= is being called. WARNING: CPU: 3 PID: 6306 at kobject_put+0x23d/0x4e0 CPU: 3 PID: 6306 Comm: 283 Tainted: G W 6.1.0-rc2-00005-g30= 7c1086d7c9 #1253 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1= .1 04/01/2014 RIP: 0010:kobject_put+0x23d/0x4e0 Call Trace: cdev_device_add+0x15e/0x1b0 __iio_device_register+0x13b4/0x1af0 [industrialio] __devm_iio_device_register+0x22/0x90 [industrialio] max517_probe+0x3d8/0x6b4 [max517] i2c_device_probe+0xa81/0xc00 When device_add() is injected fault and returns error, if dev->devt is not = set, cdev_add() is not called, cdev_del() is not needed. Fix this by checking de= v->devt in error path. Fixes: 233ed09d7fda ("chardev: add helper function to register char devs wi= th a struct device") Signed-off-by: Yang Yingliang --- The previous patch link: https://lore.kernel.org/lkml/20221025113957.693723-1-yangyingliang@huawei.c= om/ --- fs/char_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/char_dev.c b/fs/char_dev.c index ba0ded7842a7..3f667292608c 100644 --- a/fs/char_dev.c +++ b/fs/char_dev.c @@ -547,7 +547,7 @@ int cdev_device_add(struct cdev *cdev, struct device *d= ev) } =20 rc =3D device_add(dev); - if (rc) + if (rc && dev->devt) cdev_del(cdev); =20 return rc; --=20 2.25.1