From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx105.postini.com [74.125.245.105]) by kanga.kvack.org (Postfix) with SMTP id CEADE6B0062 for ; Wed, 7 Nov 2012 10:26:04 -0500 (EST) Date: Wed, 7 Nov 2012 15:25:58 +0000 From: Mel Gorman Subject: Re: [RFC PATCH 00/19] Foundation for automatic NUMA balancing Message-ID: <20121107152558.GZ8218@suse.de> References: <1352193295-26815-1-git-send-email-mgorman@suse.de> <509A2970.9000408@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <509A2970.9000408@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Zhouping Liu Cc: Peter Zijlstra , Andrea Arcangeli , Ingo Molnar , Rik van Riel , Johannes Weiner , Hugh Dickins , Thomas Gleixner , Linus Torvalds , Andrew Morton , Linux-MM , LKML , CAI Qian On Wed, Nov 07, 2012 at 05:27:12PM +0800, Zhouping Liu wrote: > > Hello Mel, > > my 2 nodes machine hit a panic fault after applied the patch > set(based on kernel-3.7.0-rc4), please review it: > > Early initialisation problem by the looks of things. Try this please ---8<--- mm: numa: Check that preferred_node_policy is initialised Zhouping Liu reported the following [ 0.000000] ------------[ cut here ]------------ [ 0.000000] kernel BUG at mm/mempolicy.c:1785! [ 0.000000] invalid opcode: 0000 [#1] SMP [ 0.000000] Modules linked in: [ 0.000000] CPU 0 .... [ 0.000000] Call Trace: [ 0.000000] [] alloc_pages_current+0xa6/0x170 [ 0.000000] [] __get_free_pages+0x14/0x50 [ 0.000000] [] kmem_cache_init+0x53/0x2d2 [ 0.000000] [] start_kernel+0x1e0/0x3c7 Problem is that early in boot preferred_nod_policy and SLUB initialisation trips up. Check it is initialised. Signed-off-by: Mel Gorman --- mm/mempolicy.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 11d4b6b..8cfa6dc 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -129,6 +129,10 @@ static struct mempolicy *get_task_policy(struct task_struct *p) node = numa_node_id(); if (node != -1) pol = &preferred_node_policy[node]; + + /* preferred_node_policy is not initialised early in boot */ + if (!pol->mode) + pol = NULL; } return pol; -- 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