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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 2B04BC433E6 for ; Thu, 18 Feb 2021 09:59:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBD1C64E68 for ; Thu, 18 Feb 2021 09:59:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230060AbhBRJyy (ORCPT ); Thu, 18 Feb 2021 04:54:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:45900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230175AbhBRIll (ORCPT ); Thu, 18 Feb 2021 03:41:41 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 343A960238; Thu, 18 Feb 2021 08:40:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613637660; bh=y1uZixkc/Teji98Qqjp10uO3bpz5x0IaskLw4jV+MyE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Fedan8NayLvVSPabiYyb1K4vttKD/LAOxtKOMnbM8/e6gFo/kAMF57PfrlUatDJcb MFcSFAAQzDpccOcW6giD1hjmNdCnxU2OEtRO12Plbzl5WtDZ3ihwWcPPRQ4y0Z10PS dId7/kchTZAfbz6G6o/OWBTG7ZvM7ADeesW67sQE= Date: Thu, 18 Feb 2021 09:40:58 +0100 From: Greg KH To: Michael Walle Cc: linux-kernel@vger.kernel.org, maz@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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210217195717.13727-1-michael@walle.cc> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 17, 2021 at 08:57:17PM +0100, 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. > > [ 0.000000] Linux version 5.11.0-next-20210217-00014-g41e0e92a2d05 (mwalle@mwalle01) (aarch64-linux-gnu-gcc (Debian 8.3.0-2) 8.3.0, GNU ld (GNU Binutils for Debian) 2.31.1) #69 SMP PREEMPT Wed Feb 17 20:47:10 CET 2021 > [..] > [ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 > [ 0.000000] Mem abort info: > [ 0.000000] ESR = 0x96000004 Back to this log, do you see: "Unable to pin filesystem for file " anywhere before this crash? thanks, greg k-h