Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751335Ab0HNFn6 (ORCPT ); Sat, 14 Aug 2010 01:43:58 -0400 Received: from 1wt.eu ([62.212.114.60]:40931 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751126Ab0HNFnz (ORCPT ); Sat, 14 Aug 2010 01:43:55 -0400 Date: Sat, 14 Aug 2010 07:43:35 +0200 From: Willy Tarreau To: Greg KH Cc: Linus Torvalds , Grant Coady , linux-kernel@vger.kernel.org, stable@kernel.org, akpm@linux-foundation.org, stable-review@kernel.org, alan@lxorguk.ukuu.org.uk Subject: Re: [Stable-review] [0/3] 2.6.27.52 stable review Message-ID: <20100814054335.GB21003@1wt.eu> References: <20100813214704.GA18960@kroah.com> <20100813230712.GA1703@suse.de> <20100814001158.GA2849@suse.de> <20100814025323.GA4779@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20100814025323.GA4779@suse.de> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1668 Lines: 36 On Fri, Aug 13, 2010 at 07:53:23PM -0700, Greg KH wrote: > On Fri, Aug 13, 2010 at 05:51:56PM -0700, Linus Torvalds wrote: > > On Fri, Aug 13, 2010 at 5:11 PM, Greg KH wrote: > > > > > > That's a warning that current->mm is null. ?I don't know enough about > > > the mm subsystem to say if this is normal or not, and I don't at first > > > glance, see how this patch could have caused this to happen. > > > > We call that whole "expand_stack()" through handle_mm_fault(), and > > that's _not_ called just for the process itself. So "current->mm" is > > sometimes simply the wrong thing to use - like when you access the VM > > of another process (during fork for the argument setup of the new VM, > > or during ptrace etc). > > > > Which is why I think commit 05fa199d45c should fix it. It makes the > > stack expansion thing use the right mm. Which it just _happened_ to do > > before, because it was always called just from the faulting code where > > current->mm happened to be the right mm. > > > > But I really don't know if there might be other issues lurking too. > > Ok, I'll go add that commit, and I unpacked my older machine that runs > the .27 kernel and will beat on it with that box tomorrow to see if > anything else pops up. Greg, I confirm that 05fa199d45c fixes the warnings. I did not have them in .51, got them with .52-rc1 and got rid of it with the patch above. Regards, Willy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/