From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arjan van de Ven Subject: Re: [RFC PATCH 02/12] On Tue, 23 Sep 2008, David Miller wrote: Date: Sun, 05 Oct 2008 08:05:09 -0700 Message-ID: <48E8D7A5.7060508@linux.intel.com> References: <20080930030825.22950.18891.stgit@jbrandeb-bw.jf.intel.com> <200810021523.45884.jbarnes@virtuousgeek.org> <20081003.134634.240211201.davem@davemloft.net> <200810031429.22598.jbarnes@virtuousgeek.org> <4807377b0810031628x43f79eferdbb9c9c264a5816e@mail.gmail.com> <4807377b0810041824u5ea472d1q4cf5ff606bd23a11@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jesse Brandeburg , Jiri Kosina , Jesse Barnes , David Miller , jesse.brandeburg@intel.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, kkeil@suse.de, agospoda@redhat.com, david.graham@intel.com, bruce.w.allan@intel.com, john.ronciak@intel.com, chris.jones@canonical.com, tim.gardner@canonical.com, airlied@gmail.com, Olaf Kirch , Linus Torvalds To: Thomas Gleixner Return-path: Received: from mga05.intel.com ([192.55.52.89]:54193 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754066AbYJEPGj (ORCPT ); Sun, 5 Oct 2008 11:06:39 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Thomas Gleixner wrote: > On Sat, 4 Oct 2008, Jesse Brandeburg wrote: >>> Exactly. The access to a ro region results in a fault. I have nowhere >>> seen that trigger, but I can reproduce the trylock() WARN_ON, which >>> confirms that there is concurrent access to the NVRAM registers. The >>> backtrace pattern is similar to the one you have seen. >> are you still getting WARN_ON *with* all the mutex based fixes already applied? > > The WARN_ON triggers with current mainline. Is there any fixlet in > Linus tree missing ? > >> with the mutex patches in place (without protection patch) we are >> still reproducing the issue, until we apply the set_memory_ro patch. > > That does not make sense to me. If the memory_ro patch is providing > _real_ protection then you _must_ run into an access violation. If not, > then the patch just papers over the real problem in some mysterious > way. > not if the bad code is doing copy_to_user .... (or similar)