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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 174A5C433E0 for ; Thu, 18 Feb 2021 08:39:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C2AE64E6F for ; Thu, 18 Feb 2021 08:39:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231254AbhBRIiW (ORCPT ); Thu, 18 Feb 2021 03:38:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:38606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229656AbhBRHci (ORCPT ); Thu, 18 Feb 2021 02:32:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 14C7364DE0; Thu, 18 Feb 2021 07:31:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613633511; bh=+5aNwyGQJIbyyZyM0+HKoT2vZqNNAffcDF+ZTPIW6gQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wsKFzax0ib+QcKM/vfGrNGYt10V6PYvW/CcX/sQn0wcRko09qAUEbaRmtU9bMlRQv zO6MlrEB6J5jKwaHz4LOzRd70CmC2m30yhIVyXkQgkMQ5cuCydeMqbdQUonEAsllS7 pVT1H/uCIT+D7mKLxjcH3xCSACoVP1ku1DhMAHsI= Date: Thu, 18 Feb 2021 08:31:46 +0100 From: Greg KH To: Marc Zyngier , Michael Walle Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de Subject: Re: [PATCH] irqdomain: remove debugfs_file from struct irq_domain Message-ID: References: <20210217195717.13727-1-michael@walle.cc> <4e4d0479b935e60a53f75ef534086476@kernel.org> <5c527bfb6f3dfe31b5c25f29418306c6@walle.cc> <87czwys6s1.wl-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87czwys6s1.wl-maz@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 17, 2021 at 09:50:38PM +0000, Marc Zyngier wrote: > On Wed, 17 Feb 2021 20:10:50 +0000, > Michael Walle wrote: > > > > Am 2021-02-17 21:02, schrieb Marc Zyngier: > > > On 2021-02-17 19:57, Michael Walle wrote: > > >> Hi Greg, > > >> > > >>> There's no need to keep around a dentry pointer to a simple file that > > >>> debugfs itself can look up when we need to remove it from the system. > > >>> So simplify the code by deleting the variable and cleaning up the > > >>> logic > > >>> around the debugfs file. > > >> > > >> This will generate the following oops on my board (arm64, > > >> freescale/fsl-ls1028a-kontron-sl28-var3-ads2.dts). In debugfs_lookup() > > >> debugfs_mount is NULL. > > > > > > That's odd. I gave it a go yesterday, and nothing blew up. > > > Which makes me wonder whether I had the debug stuff enabled > > > the first place... > > > > > > I've dropped the patch from -next for now until I figure it out > > > (probably tomorrow). > > > > Mh, maybe its my .config, I've attached it. I also noticed that > > the board boots just fine in our kernel-ci [1]. > > I reproduced here. I had disabled GENERIC_IRQ_DEBUGFS for obscure > reasons, and it caught fire as I re-enabled it. > > Adding this fixes it for me: > > diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c > index 367ff1c35f75..d8a14cf1a7b6 100644 > --- a/kernel/irq/irqdomain.c > +++ b/kernel/irq/irqdomain.c > @@ -1904,7 +1904,8 @@ static void debugfs_add_domain_dir(struct irq_domain *d) > > static void debugfs_remove_domain_dir(struct irq_domain *d) > { > - debugfs_remove(debugfs_lookup(d->name, domain_dir)); > + if (domain_dir) > + debugfs_remove(debugfs_lookup(d->name, domain_dir)); > } > > void __init irq_domain_debugfs_init(struct dentry *root) > > > Could you please check whether it works for you? Can you try this debugfs core change instead? Callers to debugfs should not have to do the above type of checking as debugfs should be much more robust than that. thanks, greg k-h diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 2fcf66473436..5aa798f52b6e 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -297,7 +297,7 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent) { struct dentry *dentry; - if (IS_ERR(parent)) + if (IS_ERR_OR_NULL(name) || IS_ERR(parent)) return NULL; if (!parent)