From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933332AbZGPUou (ORCPT ); Thu, 16 Jul 2009 16:44:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933324AbZGPUot (ORCPT ); Thu, 16 Jul 2009 16:44:49 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:48743 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933323AbZGPUos (ORCPT ); Thu, 16 Jul 2009 16:44:48 -0400 Date: Thu, 16 Jul 2009 13:44:01 -0700 From: Andrew Morton To: Stefani Seibold Cc: Valdis.Kletnieks@vt.edu, linux-kernel@vger.kernel.org Subject: Re: 2.6.31-rc1-mmotm0702 - ps command hangs inside kernel Message-Id: <20090716134401.0b1bec77.akpm@linux-foundation.org> In-Reply-To: <1247775887.10888.17.camel@wall-e> References: <47423.1247518491@turing-police.cc.vt.edu> <20090713143810.5e17bbdb.akpm@linux-foundation.org> <1247549479.30711.8.camel@wall-e> <46776.1247771564@turing-police.cc.vt.edu> <1247775887.10888.17.camel@wall-e> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.20; i486-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 On Thu, 16 Jul 2009 22:24:47 +0200 Stefani Seibold wrote: > On Thu, 16 Jul 2009, 15:12 -0400 Valdis.Kletnieks@vt.edu said: > > On Tue, 14 Jul 2009 07:31:19 +0200, Stefani Seibold said: > > > Am Montag, den 13.07.2009, 14:38 -0700 schrieb Andrew Morton: > > > > On Mon, 13 Jul 2009 16:54:51 -0400 > > > > Valdis.Kletnieks@vt.edu wrote: > > > > > > > > > Several times recently, I've had the 'ps' command hang inside the kernel > > > > > for extended periods of time - usually around 1100 seconds, but today I > > > > > had one that hung there for 2351 seconds. > > > > > i am the author of the get_stack_usage_bytes(). Because i have currently > > > no 64bit machine running, i am not able to analyse your problem. Does it > > > only happen on 32bit application on a 64bit kernel? Is it only affected > > > to pcsd? > > > > I've only seen it happen to pcscd. However, most of the time it's one of > > the very few 32-bit apps running on my laptop (I've got exactly *one* legacy > > app for a secure-token that is stuck in 32-bit land). So I can't tell if it's > > a generic 32-bit issue. > > > > It's possible that one of the two follow_page() entries is stale and just > > happened to be left on the stack. A large chunk of proc_pid_status() is > > inlined, so it's possible that two calls were made and left their return > > addresses in different locations on the stack. > > > > I am pretty sure that follow_page+0x28 is the correct one, as I see it > > in 2 more tracebacks today (see below)... > > The stack trace looks like you there is a old version included in the > 2.6.31-rc1-mmotm0702 patches. > > I switch to walk_page_range() function since patch version V0.9 dated > from Jun 10 2009. Here is the link to the lkml patchwork: > > http://patchwork.kernel.org/patch/32210/ > > I do the map examination exactly in the same way like the function used > for /proc//smaps. So i think this version should do it without side > effects. > > Can you tell me were you downloaded the 2.6.31-rc1-mmotm0702 patch? It would have been version 08. I've now updated to v11.