From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751458AbWGMNvR (ORCPT ); Thu, 13 Jul 2006 09:51:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751472AbWGMNvR (ORCPT ); Thu, 13 Jul 2006 09:51:17 -0400 Received: from e34.co.us.ibm.com ([32.97.110.152]:55702 "EHLO e34.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751458AbWGMNvQ (ORCPT ); Thu, 13 Jul 2006 09:51:16 -0400 Subject: Re: Random panics seen in 2.6.18-rc1 From: Chandra Seetharaman Reply-To: sekharan@us.ibm.com To: Ingo Molnar Cc: torvalds@asdl.org, akpm@osdl.org, LKML , Shailabh Nagar , Balbir Singh , Arjan van de Ven In-Reply-To: <20060713071221.GA31349@elte.hu> References: <1152763195.11343.16.camel@linuxchandra> <20060713071221.GA31349@elte.hu> Content-Type: text/plain Organization: IBM Date: Thu, 13 Jul 2006 06:51:12 -0700 Message-Id: <1152798672.18415.2.camel@linuxchandra> Mime-Version: 1.0 X-Mailer: Evolution 2.0.4 (2.0.4-7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2006-07-13 at 09:12 +0200, Ingo Molnar wrote: > * Chandra Seetharaman wrote: > > > By adding one patch at a time to 2.6.17's mm/slab.c, I found that the > > following patch is the cause of the panic. > > -------------- > > [PATCH] lockdep: annotate SLAB code > > great debugging! Thanks. > > I have reviewed that patch, and there's only one chunk that could > possibly have a functional effect. The patch below undoes it - does that > fix the crashes you are seeing? [If you have lockdep enabled then this > patch will cause a lockdep false positive - ignore that one for now, it > shouldnt impact the crash scenario itself.] > started the tests with this patch now. will report back in couple of hours... earlier if it crashes again :), which i doubt. Thanks & regards, chandra > Ingo > > ---------------------> > Subject: revert slab.c locking change > From: Ingo Molnar > > Chandra Seetharaman reported SLAB crashes caused by the slab.c > lock annotation patch. There is only one chunk of that patch > that has a material effect on the slab logic - this patch > undoes that chunk. > > Signed-off-by: Ingo Molnar > --- > mm/slab.c | 9 --------- > 1 file changed, 9 deletions(-) > > Index: linux/mm/slab.c > =================================================================== > --- linux.orig/mm/slab.c > +++ linux/mm/slab.c > @@ -3100,16 +3100,7 @@ static void free_block(struct kmem_cache > if (slabp->inuse == 0) { > if (l3->free_objects > l3->free_limit) { > l3->free_objects -= cachep->num; > - /* > - * It is safe to drop the lock. The slab is > - * no longer linked to the cache. cachep > - * cannot disappear - we are using it and > - * all destruction of caches must be > - * serialized properly by the user. > - */ > - spin_unlock(&l3->list_lock); > slab_destroy(cachep, slabp); > - spin_lock(&l3->list_lock); > } else { > list_add(&slabp->list, &l3->slabs_free); > } -- ---------------------------------------------------------------------- Chandra Seetharaman | Be careful what you choose.... - sekharan@us.ibm.com | .......you may get it. ----------------------------------------------------------------------