Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932257AbaAWPFK (ORCPT ); Thu, 23 Jan 2014 10:05:10 -0500 Received: from cantor2.suse.de ([195.135.220.15]:59239 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932215AbaAWPFD (ORCPT ); Thu, 23 Jan 2014 10:05:03 -0500 Date: Thu, 23 Jan 2014 16:05:01 +0100 From: Jan Kara To: Dave Jones Cc: Linus Torvalds , Jan Kara , Linux Kernel , Jiri Kosina Subject: Re: fanotify use after free. Message-ID: <20140123150501.GC28796@quack.suse.cz> References: <20140122062730.GA25601@redhat.com> <20140122233622.GB27916@quack.suse.cz> <20140123003240.GA25547@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140123003240.GA25547@redhat.com> 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 On Wed 22-01-14 19:32:40, Dave Jones wrote: > On Wed, Jan 22, 2014 at 04:08:52PM -0800, Linus Torvalds wrote: > > On Wed, Jan 22, 2014 at 3:36 PM, Jan Kara wrote: > > > > > > But refcounting seems like an overkill for this - there is exactly one > > > fanotify_response_event structure iff it is a permission event. So > > > something like the (completely untested) attached patch should fix the > > > problem. But I agree it's a bit ugly so we might want something different. > > > I'll try to think about something better tomorrow. > > > > Ok, In the meantime, Dave, can you verify whether this hacky patch > > fixes your problem? > > It actually seems worse. I see the tail end of what looks like a slab corruption > trace, and then a total lockup. And of course none of this makes it over ttyUSB0 > because it happens so early. Grr. Drat. Since this seems reasonably reproducible, I'll try to reproduce and debug this (it seems systemd is using fanotify in a way that triggers this). Thanks for testing. Honza -- Jan Kara SUSE Labs, CR -- 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/