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 AFEF6C4332F for ; Sat, 12 Nov 2022 09:34:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234811AbiKLJeY (ORCPT ); Sat, 12 Nov 2022 04:34:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234683AbiKLJeV (ORCPT ); Sat, 12 Nov 2022 04:34:21 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31F6E140D8 for ; Sat, 12 Nov 2022 01:34:20 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A85A4609EB for ; Sat, 12 Nov 2022 09:34:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88390C433D6; Sat, 12 Nov 2022 09:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1668245659; bh=65exbud4oDHB8q1YGgMYLfLKD5iC+Ky9YXJn0Mhqr04=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=swyT4o2zFxp9yX7LQ6kGrOCZEhw690k8I8hvkpIUK94p8JaN0qKiAs5xlcBxOa0br ju4+bhRxTv4TabkqGzCA9mCCi22DUaG84JOq4l9tw9ElPfGE1qGKlS7OvyPI02jlgr 2ygXrK24Zn2y4YFJnu8yWDbi8fVSwgm8fou1U9us= Date: Sat, 12 Nov 2022 10:34:16 +0100 From: Greg Kroah-Hartman To: Liu Shixin Cc: Thomas Gleixner , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] genirq/irqdesc: hide illegible sysfs warning of kobject_del() Message-ID: References: <20221112093939.616270-1-liushixin2@huawei.com> <137bd5cc-0be9-6228-82e2-a75b53e5a2ae@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <137bd5cc-0be9-6228-82e2-a75b53e5a2ae@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 12, 2022 at 05:19:50PM +0800, Liu Shixin wrote: > > > 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 fix that. > >> 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? The code itself knows what just failed, handle the error case there properly. > >> 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(). And it is wrong there as well. Do not copy bad patterns please. thanks, greg k-h