From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261672AbULTWfd (ORCPT ); Mon, 20 Dec 2004 17:35:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261673AbULTWfc (ORCPT ); Mon, 20 Dec 2004 17:35:32 -0500 Received: from omx1-ext.sgi.com ([192.48.179.11]:35755 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S261672AbULTWfY (ORCPT ); Mon, 20 Dec 2004 17:35:24 -0500 Date: Mon, 20 Dec 2004 16:35:18 -0600 From: Brent Casavant Reply-To: Brent Casavant To: William Lee Irwin III cc: linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: Oops on 2.4.x invalid procfs i_ino value In-Reply-To: <20041218004703.GE771@holomorphy.com> Message-ID: References: <20041218003835.GD771@holomorphy.com> <20041218004703.GE771@holomorphy.com> Organization: "Silicon Graphics, Inc." MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 17 Dec 2004, William Lee Irwin III wrote: > On Fri, Dec 17, 2004 at 04:49:44PM -0600, Brent Casavant wrote: > >> On a related note, if it matters, on about half the crash dumps I've > >> looked at, I see a pid of 0 has been assigned to a user process, > >> tripping this same problem. I suspect there's another bug somewhere > >> that's allowing a pid of 0 to be chosen in the first place -- but I > >> don't totally discount that this problem may lay in SGI's patches to > >> this particular kernel -- I'll need to take a more thorough look. > > On Fri, Dec 17, 2004 at 04:38:35PM -0800, William Lee Irwin III wrote: > > That's rather ominous. I'll pore over pid.c and see what's going on. > > Also, does the pid.c in your kernel version match 2.6.x-CURRENT? > > Ouch, 2.4.21; this will be trouble. So next, what patches atop 2.4.21? I wouldn't worry about the pid=0 issue -- I think it's most likely due to the PAGG patches (http://oss.sgi.com/projects/pagg) causing some sort of problem at process teardown (all the pid=0 processes are in the process of exiting). I'm more concerned about the (0 == pid & 0xffff) bug, which is present in the unpatched mainline 2.4.x kernel. It seems that the easiest fix is marking such pids as in-use at pidmap allocation, so that they are never assigned to real tasks. I've got the code almost done, but need to port it to top-of-tree before submitting a patch. Brent -- Brent Casavant If you had nothing to fear, bcasavan@sgi.com how then could you be brave? Silicon Graphics, Inc. -- Queen Dama, Source Wars