From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 402B06B004D for ; Fri, 15 May 2009 04:08:47 -0400 (EDT) Subject: Re: kernel BUG at mm/slqb.c:1411! From: Pekka Enberg In-Reply-To: <20090515083726.F5BF.A69D9226@jp.fujitsu.com> References: <1242289830.21646.5.camel@penberg-laptop> <20090514175332.9B7B.A69D9226@jp.fujitsu.com> <20090515083726.F5BF.A69D9226@jp.fujitsu.com> Date: Fri, 15 May 2009 11:08:51 +0300 Message-Id: <1242374931.21646.30.camel@penberg-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Minchan Kim , linux-mm , LKML , Nick Piggin , matthew.r.wilcox@intel.com List-ID: Hi Motohiro-san, On Wed, 2009-05-13 at 17:37 +0900, Minchan Kim wrote: > > > > On Wed, 13 May 2009 16:42:37 +0900 (JST) > > > > KOSAKI Motohiro wrote: > > > > > > > > Hmm. I don't know slqb well. > > > > So, It's just my guess. > > > > > > > > We surely increase l->nr_partial in __slab_alloc_page. > > > > In between l->nr_partial++ and call __cache_list_get_page, Who is decrease l->nr_partial again. > > > > After all, __cache_list_get_page return NULL and hit the VM_BUG_ON. > > > > > > > > Comment said : > > > > > > > > /* Protects nr_partial, nr_slabs, and partial */ > > > > spinlock_t page_lock; > > > > > > > > As comment is right, We have to hold the l->page_lock ? > > > > > > Makes sense. Nick? Motohiro-san, can you try this patch please? > > > > This issue is very rarely. please give me one night. On Fri, 2009-05-15 at 08:38 +0900, KOSAKI Motohiro wrote: > -ENOTREPRODUCED > > I guess your patch is right fix. thanks! Thank you so much for testing! Nick seems to have gone silent for the past few days so I went ahead and merged the patch. Did you have CONFIG_PROVE_LOCKING enabled, btw? I think I got the lock order correct but I don't have a NUMA machine to test it with here. Pekka -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org