From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932361Ab0CaABl (ORCPT ); Tue, 30 Mar 2010 20:01:41 -0400 Received: from kroah.org ([198.145.64.141]:45413 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756840Ab0C3XSr (ORCPT ); Tue, 30 Mar 2010 19:18:47 -0400 X-Mailbox-Line: From linux@linux.site Tue Mar 30 15:56:59 2010 Message-Id: <20100330225658.504101661@linux.site> User-Agent: quilt/0.47-14.9 Date: Tue, 30 Mar 2010 15:56:08 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Miao Xie , David Rientjes , Paul Menage , Li Zefan , Ingo Molnar , Greg Kroah-Hartman Subject: [090/116] cpuset: fix the problem that cpuset_mem_spread_node() returns an offline node In-Reply-To: <20100330230600.GA28802@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ From: Miao Xie commit 5ab116c9349ef52d6fbd2e2917a53f13194b048e upstream. cpuset_mem_spread_node() returns an offline node, and causes an oops. This patch fixes it by initializing task->mems_allowed to node_states[N_HIGH_MEMORY], and updating task->mems_allowed when doing memory hotplug. Signed-off-by: Miao Xie Acked-by: David Rientjes Reported-by: Nick Piggin Tested-by: Nick Piggin Cc: Paul Menage Cc: Li Zefan Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- init/main.c | 2 +- kernel/cpuset.c | 20 ++++++++++++-------- kernel/kthread.c | 2 +- 3 files changed, 14 insertions(+), 10 deletions(-) --- a/init/main.c +++ b/init/main.c @@ -846,7 +846,7 @@ static int __init kernel_init(void * unu /* * init can allocate pages on any node */ - set_mems_allowed(node_possible_map); + set_mems_allowed(node_states[N_HIGH_MEMORY]); /* * init can run on any cpu. */ --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -921,9 +921,6 @@ static int update_cpumask(struct cpuset * call to guarantee_online_mems(), as we know no one is changing * our task's cpuset. * - * Hold callback_mutex around the two modifications of our tasks - * mems_allowed to synchronize with cpuset_mems_allowed(). - * * While the mm_struct we are migrating is typically from some * other task, the task_struct mems_allowed that we are hacking * is for our current task, which must allocate new pages for that @@ -1392,11 +1389,10 @@ static void cpuset_attach(struct cgroup_ if (cs == &top_cpuset) { cpumask_copy(cpus_attach, cpu_possible_mask); - to = node_possible_map; } else { guarantee_online_cpus(cs, cpus_attach); - guarantee_online_mems(cs, &to); } + guarantee_online_mems(cs, &to); /* do per-task migration stuff possibly for each in the threadgroup */ cpuset_attach_task(tsk, &to, cs); @@ -2091,15 +2087,23 @@ static int cpuset_track_online_cpus(stru static int cpuset_track_online_nodes(struct notifier_block *self, unsigned long action, void *arg) { + nodemask_t oldmems; + cgroup_lock(); switch (action) { case MEM_ONLINE: - case MEM_OFFLINE: + oldmems = top_cpuset.mems_allowed; mutex_lock(&callback_mutex); top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; mutex_unlock(&callback_mutex); - if (action == MEM_OFFLINE) - scan_for_empty_cpusets(&top_cpuset); + update_tasks_nodemask(&top_cpuset, &oldmems, NULL); + break; + case MEM_OFFLINE: + /* + * needn't update top_cpuset.mems_allowed explicitly because + * scan_for_empty_cpusets() will update it. + */ + scan_for_empty_cpusets(&top_cpuset); break; default: break; --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -196,7 +196,7 @@ int kthreadd(void *unused) set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); set_cpus_allowed_ptr(tsk, cpu_all_mask); - set_mems_allowed(node_possible_map); + set_mems_allowed(node_states[N_HIGH_MEMORY]); current->flags |= PF_NOFREEZE | PF_FREEZER_NOSIG;