From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765643AbZFLOFB (ORCPT ); Fri, 12 Jun 2009 10:05:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765414AbZFLOEg (ORCPT ); Fri, 12 Jun 2009 10:04:36 -0400 Received: from mga14.intel.com ([143.182.124.37]:46881 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764362AbZFLOEf (ORCPT ); Fri, 12 Jun 2009 10:04:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.42,209,1243839600"; d="scan'208";a="153577650" Date: Fri, 12 Jun 2009 22:04:26 +0800 From: Wu Fengguang To: Andi Kleen Cc: Andrew Morton , LKML , Nick Piggin , Hugh Dickins , "riel@redhat.com" , "chris.mason@oracle.com" , "linux-mm@kvack.org" Subject: Re: [PATCH 2/5] HWPOISON: fix tasklist_lock/anon_vma locking order Message-ID: <20090612140426.GA8481@localhost> References: <20090611142239.192891591@intel.com> <20090611144430.540500784@intel.com> <20090612100308.GD25568@one.firstfloor.org> <20090612132714.GB6751@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090612132714.GB6751@localhost> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 12, 2009 at 09:27:14PM +0800, Wu Fengguang wrote: > On Fri, Jun 12, 2009 at 06:03:08PM +0800, Andi Kleen wrote: > > On Thu, Jun 11, 2009 at 10:22:41PM +0800, Wu Fengguang wrote: > > > To avoid possible deadlock. Proposed by Nick Piggin: > > > > I disagree with the description. There's no possible deadlock right now. > > It would be purely out of paranoia. > > > > > > > > You have tasklist_lock(R) nesting outside i_mmap_lock, and inside anon_vma > > > lock. And anon_vma lock nests inside i_mmap_lock. > > > > > > This seems fragile. If rwlocks ever become FIFO or tasklist_lock changes > > > > I was a bit dubious on this reasoning. If rwlocks become FIFO a lot of > > stuff will likely break. > > > > > type (maybe -rt kernels do it), then you could have a task holding > > > > I think they tried but backed off quickly again > > > > It's ok with a less scare-mongering description. > > Why not merge it into the original patch and add a simple changelog > line there? I tried the last 6.5 patchset and it didn't apply cleanly > to the latest -mm tree. And this patch was updated: Andy, please apply this patch too. It fixed a kernel panic: when invalid PFN is feed to the debug injection interface, action_result() will try to do a pfn_to_page() on it.. Thanks, Fengguang --- mm/memory-failure.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- sound-2.6.orig/mm/memory-failure.c +++ sound-2.6/mm/memory-failure.c @@ -439,7 +439,9 @@ void memory_failure(unsigned long pfn, i struct page *p; if (!pfn_valid(pfn)) { - action_result(pfn, "memory outside kernel control", IGNORED); + printk(KERN_ERR + "MCE %#lx: memory outside kernel control: Ignored\n", + pfn); return; }