From patchwork Wed Nov 16 01:27:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Jun X-Patchwork-Id: 625428 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 3ECBEC433FE for ; Wed, 16 Nov 2022 01:29:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231639AbiKPB3F (ORCPT ); Tue, 15 Nov 2022 20:29:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229961AbiKPB3E (ORCPT ); Tue, 15 Nov 2022 20:29:04 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49A4ADEB7; Tue, 15 Nov 2022 17:29:03 -0800 (PST) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NBlmt6qSQzHvrV; Wed, 16 Nov 2022 09:28:30 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 16 Nov 2022 09:29:01 +0800 Received: from mdc.huawei.com (10.175.112.208) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 16 Nov 2022 09:29:00 +0800 From: Chen Jun To: , , , , CC: Subject: [PATCH] watchdog: Fix kmemleak in watchdog_cdev_register Date: Wed, 16 Nov 2022 01:27:14 +0000 Message-ID: <20221116012714.102066-1-chenjun102@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.175.112.208] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org kmemleak reports memory leaks in watchdog_dev_register, as follows: unreferenced object 0xffff888116233000 (size 2048): comm ""modprobe"", pid 28147, jiffies 4353426116 (age 61.741s) hex dump (first 32 bytes): 80 fa b9 05 81 88 ff ff 08 30 23 16 81 88 ff ff .........0#..... 08 30 23 16 81 88 ff ff 00 00 00 00 00 00 00 00 .0#............. backtrace: [<000000007f001ffd>] __kmem_cache_alloc_node+0x157/0x220 [<000000006a389304>] kmalloc_trace+0x21/0x110 [<000000008d640eea>] watchdog_dev_register+0x4e/0x780 [watchdog] [<0000000053c9f248>] __watchdog_register_device+0x4f0/0x680 [watchdog] [<00000000b2979824>] watchdog_register_device+0xd2/0x110 [watchdog] [<000000001f730178>] 0xffffffffc10880ae [<000000007a1a8bcc>] do_one_initcall+0xcb/0x4d0 [<00000000b98be325>] do_init_module+0x1ca/0x5f0 [<0000000046d08e7c>] load_module+0x6133/0x70f0 ... unreferenced object 0xffff888105b9fa80 (size 16): comm ""modprobe"", pid 28147, jiffies 4353426116 (age 61.741s) hex dump (first 16 bytes): 77 61 74 63 68 64 6f 67 31 00 b9 05 81 88 ff ff watchdog1....... backtrace: [<000000007f001ffd>] __kmem_cache_alloc_node+0x157/0x220 [<00000000486ab89b>] __kmalloc_node_track_caller+0x44/0x1b0 [<000000005a39aab0>] kvasprintf+0xb5/0x140 [<0000000024806f85>] kvasprintf_const+0x55/0x180 [<000000009276cb7f>] kobject_set_name_vargs+0x56/0x150 [<00000000a92e820b>] dev_set_name+0xab/0xe0 [<00000000cec812c6>] watchdog_dev_register+0x285/0x780 [watchdog] [<0000000053c9f248>] __watchdog_register_device+0x4f0/0x680 [watchdog] [<00000000b2979824>] watchdog_register_device+0xd2/0x110 [watchdog] [<000000001f730178>] 0xffffffffc10880ae [<000000007a1a8bcc>] do_one_initcall+0xcb/0x4d0 [<00000000b98be325>] do_init_module+0x1ca/0x5f0 [<0000000046d08e7c>] load_module+0x6133/0x70f0 ... The reason is that put_device is not be called if cdev_device_add fails and wdd->id != 0. watchdog_cdev_register wd_data = kzalloc [1] err = dev_set_name [2] .. err = cdev_device_add if (err) { if (wdd->id == 0) { // wdd->id != 0 .. } return err; // [1],[2] would be leaked To fix it, call put_device in all wdd->id cases. Fixes: 72139dfa2464 ("watchdog: Fix the race between the release of watchdog_core_data and cdev") Signed-off-by: Chen Jun Reviewed-by: Guenter Roeck --- drivers/watchdog/watchdog_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 55574ed42504..fdffa6859dde 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1061,8 +1061,8 @@ static int watchdog_cdev_register(struct watchdog_device *wdd) if (wdd->id == 0) { misc_deregister(&watchdog_miscdev); old_wd_data = NULL; - put_device(&wd_data->dev); } + put_device(&wd_data->dev); return err; }