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 36B88C4332F for ; Sat, 12 Nov 2022 09:20:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234693AbiKLJT7 (ORCPT ); Sat, 12 Nov 2022 04:19:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230170AbiKLJTy (ORCPT ); Sat, 12 Nov 2022 04:19:54 -0500 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FCBDB7CC for ; Sat, 12 Nov 2022 01:19:53 -0800 (PST) Received: from dggpemm500021.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4N8VQH0cjLz15M79; Sat, 12 Nov 2022 17:19:35 +0800 (CST) Received: from dggpemm100009.china.huawei.com (7.185.36.113) by dggpemm500021.china.huawei.com (7.185.36.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 12 Nov 2022 17:19:51 +0800 Received: from [10.174.179.24] (10.174.179.24) by dggpemm100009.china.huawei.com (7.185.36.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Sat, 12 Nov 2022 17:19:50 +0800 Subject: Re: [PATCH] genirq/irqdesc: hide illegible sysfs warning of kobject_del() To: Greg Kroah-Hartman References: <20221112093939.616270-1-liushixin2@huawei.com> CC: Thomas Gleixner , "Rafael J . Wysocki" , From: Liu Shixin Message-ID: <137bd5cc-0be9-6228-82e2-a75b53e5a2ae@huawei.com> Date: Sat, 12 Nov 2022 17:19:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.24] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggpemm100009.china.huawei.com (7.185.36.113) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/11/12 16:59, Greg Kroah-Hartman wrote: > On Sat, Nov 12, 2022 at 05:39:39PM +0800, Liu Shixin wrote: >> If irq_sysfs_add() failed, system will report a warning but don't call >> kobject_put() to release the descriptor. > I can not parse this sentance :( irq_sysfs_add() call kobject_add(). If kobject_add() failed, will print "Failed to add kobject for irq". But not call kobject_put(). > >> Then in irq_sysfs_del(), we continue to call kobject_del(). In such >> situation, kobject_del() will complains about a object with no parent >> like this: > Then we should not be calling irq_sysfs_del() if the call failed. That > is the real fix here. If so, should I add a variable to record whether kobject has alreadly added or not? >> kernfs: can not remove 'actions', no directory >> WARNING: CPU: 0 PID: 277 at fs/kernfs/dir.c:1615 kernfs_remove_by_name_ns+0xd5/0xe0 >> [...] >> Call Trace: >> >> remove_files.isra.0+0x3f/0xb0 >> sysfs_remove_group+0x68/0xe0 >> sysfs_remove_groups+0x41/0x70 >> __kobject_del+0x45/0xc0 >> kobject_del+0x2a/0x40 >> free_desc+0x44/0x70 >> irq_free_descs+0x5d/0x90 >> [...] >> >> Use kobj->state_in_sysfs to check whether kobject is added succeed. And >> if not, we should not call kobject_del(). > That does not describe what you are doing here at all. Sorry, I forget to update... > >> Signed-off-by: Liu Shixin >> --- >> kernel/irq/irqdesc.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c >> index a91f9001103c..a820d96210d4 100644 >> --- a/kernel/irq/irqdesc.c >> +++ b/kernel/irq/irqdesc.c >> @@ -300,10 +300,11 @@ static void irq_sysfs_del(struct irq_desc *desc) >> /* >> * If irq_sysfs_init() has not yet been invoked (early boot), then >> * irq_kobj_base is NULL and the descriptor was never added. >> + * And the descriptor may be added failed. >> * kobject_del() complains about a object with no parent, so make >> * it conditional. >> */ >> - if (irq_kobj_base) >> + if (irq_kobj_base && desc->kobj.parent) > How would the parent be NULL? Parent devices always stick around until > the child is removed, otherwise something is really wrong here. You > should never have to look at the parent. irq_sysfs_add() call kobject_add(). If kobject_add() failed, the parent will be NULL. You can find the same check of kobj->parent in cpuid_cpu_offline(). thanks, Liu Shixin . > > thanks, > > greg k-h > . >