Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757849AbcDAGKr (ORCPT ); Fri, 1 Apr 2016 02:10:47 -0400 Received: from mga11.intel.com ([192.55.52.93]:44366 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754346AbcDAGKq (ORCPT ); Fri, 1 Apr 2016 02:10:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,426,1455004800"; d="scan'208";a="936032857" Message-ID: <1459491088.4199.2.camel@linux.intel.com> Subject: Re: [PATCH] kernfs: Move faulting copy_user operations outside of the mutex From: Joonas Lahtinen To: Greg Kroah-Hartman Cc: Tejun Heo , Chris Wilson , Daniel Vetter , intel-gfx@lists.freedesktop.org, Ville =?ISO-8859-1?Q?Syrj=E4l=E4?= , NeilBrown , linux-kernel@vger.kernel.org Date: Fri, 01 Apr 2016 09:11:28 +0300 In-Reply-To: <20160331201520.GA22511@kroah.com> References: <1459421106-17788-1-git-send-email-chris@chris-wilson.co.uk> <20160331164915.GC24661@htj.duckdns.org> <1459445405.8191.32.camel@linux.intel.com> <20160331201520.GA22511@kroah.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2 (3.18.5.2-1.fc23) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 49 On to, 2016-03-31 at 13:15 -0700, Greg Kroah-Hartman wrote: > On Thu, Mar 31, 2016 at 08:30:05PM +0300, Joonas Lahtinen wrote: > > > > On to, 2016-03-31 at 12:49 -0400, Tejun Heo wrote: > > > > > > On Thu, Mar 31, 2016 at 11:45:06AM +0100, Chris Wilson wrote: > > > > > > > > > > > > A fault in a user provided buffer may lead anywhere, and lockdep warns > > > > that we have a potential deadlock between the mm->mmap_sem and the > > > > kernfs file mutex: > > > ... > > > > > > > > > > > > Reported-by: Ville Syrjälä > > > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94350 > > > > Signed-off-by: Chris Wilson > > > > Reviewed-by: Joonas Lahtinen > > > > Cc: Ville Syrjälä > > > > Cc: Joonas Lahtinen > > > > Cc: Tejun Heo > > > > Cc: Greg Kroah-Hartman > > > > Cc: NeilBrown > > > > Cc: linux-kernel@vger.kernel.org > > > Acked-by: Tejun Heo > > > > > Thanks. > > > > I have applied this locally to our repo to be included into our CI > > builds. > > > > We will drop the local patch once this waterfalls from upstream to our > > drm-intel-nightly repo. > So is this something that needs to get into 4.6-final because it > resolves a reported issue?  Or can it wait for 4.7-rc1? > It is only a getting rid of a lockdep splat describing a scenario very unlikely to ever happen, so it can wait for 4.7-rc1. Regards, Joonas > thanks, > > greg k-h -- Joonas Lahtinen Open Source Technology Center Intel Corporation