Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752407Ab3FZPYx (ORCPT ); Wed, 26 Jun 2013 11:24:53 -0400 Received: from mail.free-electrons.com ([94.23.35.102]:49144 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751728Ab3FZPYu (ORCPT ); Wed, 26 Jun 2013 11:24:50 -0400 Date: Wed, 26 Jun 2013 17:24:46 +0200 From: Thomas Petazzoni To: sedat.dilek@gmail.com Cc: linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Al Viro , Jens Axboe , linux-fsdevel , Miklos Szeredi , fuse-devel@lists.sourceforge.net, Stephen Rothwell , Arnd Bergmann , Greg Kroah-Hartman Subject: Re: linux-next: Tree for Jun 26 [ vfs | block | fuse (cpuidle) releated? ] Message-ID: <20130626172446.51f0bd5f@skate> In-Reply-To: References: Organization: Free Electrons X-Mailer: Claws Mail 3.9.1 (GTK+ 2.24.17; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1666 Lines: 47 Dear Sedat Dilek, On Wed, 26 Jun 2013 16:50:55 +0200, Sedat Dilek wrote: > [ TO/CC char-misc folks ] > > The CULPRIT commit [1] due to my git-bisecting is: > > commit 585d98e00ba7a5e2abe65f7a1eff631cb612289b > "char: misc: assign file->private_data in all cases" > > After reverting it, my system boots up fine again. > > Can someone from the char-misc folks look at that? Ok. My understanding is that the misc device registered by fs/fuse/dev.c:fuse_dev_init() makes the assumption that file->private_data == NULL when a misc device is opened. But I'm not sure to fully understand the code flow of the FUSE filesystem. And since it doesn't provide its own implementation of the ->open() operation, the misc infrastructure was leaving the file->private_data defined to NULL before my patch. With my patch, the file->private_data gets assigned unconditionally (regardless of whether the misc driver provides or does not provide a ->open() operation) which modifies the unwritten assumption that fuse was making about the initial value of file->private_data. I believe the assumption made by fuse over the initial value of this variable is a bit fragile. Maybe the FUSE code needs to be slightly adjusted to not make this assumption? Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- 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/