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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,T_DKIMWL_WL_HIGH autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id 0126BC433EF for ; Wed, 13 Jun 2018 04:59:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D54D2086A for ; Wed, 13 Jun 2018 04:59:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="kwsf4ut7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9D54D2086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933981AbeFME7Q (ORCPT ); Wed, 13 Jun 2018 00:59:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:41728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933611AbeFME7P (ORCPT ); Wed, 13 Jun 2018 00:59:15 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8AE852086A; Wed, 13 Jun 2018 04:59:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1528865955; bh=PYkZgmkiMP4jtBtIzJArYafvX4+KnJWWru+jtyp1NYo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kwsf4ut79h/XBOyXAM6Ufs2OdmbcvzSNEG4EtjU7oQ8oHEnb5kM4PHXBySJHij9Ak T4ByG/6gJNtWRRQ5WjhZesiHIP8ccLTJnFtmnsTn/bMYVAdKfyljzXNXzyvr0zdcTh pWK7ZIMg6i3A/VJFKZnYCSN9YZ5qYkGneMc4q67g= Date: Wed, 13 Jun 2018 06:58:53 +0200 From: Greg Kroah-Hartman To: John Stultz Cc: Thomas Richter , Kees Cook , lkml Subject: Re: REGRESSION?: debugfs: inode: debugfs_create_dir uses mode permission from parent Message-ID: <20180613045853.GB1246@kroah.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 12, 2018 at 03:40:41PM -0700, John Stultz wrote: > Hey all, > I noticed recently that linus/master (plus patches) stopped booting > to UI on HiKey960, and I bisected the issue down to: > 92170b62f1c1 ("debugfs: inode: debugfs_create_dir uses mode permission > from parent") > > On the HiKey960 board, we mount debugfs via: > mount debugfs /sys/kernel/debug /sys/kernel/debug mode=755 > > But since the change, it seems most of the nodes in /sys/kernel/debug > are: drwx------ > > Which ends up breaking the egl library, keeping it from loading. While the debugfs change is now reverted in Linus's tree, I find it "odd" that a debugfs change would cause egl from loading entirely. No userspace code should depend on debugfs files being there or not. If it does, that's a bug as debugfs is for _debugging_ stuff, it should not be an interface between user/kernel that userspace requires for basic functionality like booting. And yes, I know all about the crazy qualcom batter api, where they shoved it into debugfs and ignored the built-in kernel api, that should be fixed now. If this is a new one-of-those types of problem, I need to know so it can get resolved. thanks, greg k-h