Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757739Ab3DAUeu (ORCPT ); Mon, 1 Apr 2013 16:34:50 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:39636 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757422Ab3DAUet (ORCPT ); Mon, 1 Apr 2013 16:34:49 -0400 Date: Mon, 1 Apr 2013 21:34:46 +0100 From: Al Viro To: Linus Torvalds Cc: Dave Jones , Linux Kernel , Greg Kroah-Hartman Subject: Re: Yet another pipe related oops. Message-ID: <20130401203445.GA20862@ZenIV.linux.org.uk> References: <20130311180543.GF21522@ZenIV.linux.org.uk> <20130312130614.GA32237@ZenIV.linux.org.uk> <20130312194353.GI21522@ZenIV.linux.org.uk> <20130327135127.GB1738@redhat.com> <20130327152030.GY21522@ZenIV.linux.org.uk> <20130327174506.GZ21522@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130327174506.GZ21522@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1381 Lines: 26 On Wed, Mar 27, 2013 at 05:45:06PM +0000, Al Viro wrote: > We shouldn't, at least not for something that has been successfully > opened. I've a patch series cleaning that up a bit in the local > queue; will check for bitrot and throw into for-next. Egads... OK, that has gone more than slightly out of control - right now vfs.git#for-next is at 106 commits, -3.6KLoC balance and *still* hadn't reached the ->f_op part of that work ;-/ OTOH, procfs-related code got a lot cleaner and we actually have a chance to make the guts of proc_dir_entry private to fs/proc now... I'll cull the outright bug fixes into for-linus and push it your way... The thing that really worries me is debugfs; that fscker sets whatever file_operations it's got from the driver that registered a file there and sticks that into ->i_fop. When we try to open() that, we get try_module_get() ->i_fop->owner; so far, so good, but what if the driver has just been removed *and* file_operations instance we are looking at has already been freed? IOW, how do we deal with a race between attempt to open a debugfs file and its removal on driver unload? Greg? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/