This one fixed the oops for me, thanks for working on it.
Reported-and-tested-by: Nick Piggin <npiggin@xxxxxxx>
It could be a stable@ candidate because it trivially oopses
when the cpuset_mem_spread_node option is used.
On Tue, Mar 16, 2010 at 08:10:43PM +0800, Miao Xie wrote:
> 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 <miaox@xxxxxxxxxxxxxx>
> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
> ---
> init/main.c | 2 +-
> kernel/cpuset.c | 20 ++++++++++++--------
> kernel/kthread.c | 2 +-
> 3 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/init/main.c b/init/main.c
> index a1ab78c..cbead27 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -858,7 +858,7 @@ static int __init kernel_init(void * unused)
> /*
> * 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.
> */
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index ba401fa..5d38bd7 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -920,9 +920,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
> * 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
> @@ -1391,11 +1388,10 @@ static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
>
> 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);
> @@ -2090,15 +2086,23 @@ static int cpuset_track_online_cpus(struct notifier_block *unused_nb,
> 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;
> diff --git a/kernel/kthread.c b/kernel/kthread.c
> index 82ed0ea..83911c7 100644
> --- a/kernel/kthread.c
> +++ b/kernel/kthread.c
> @@ -219,7 +219,7 @@ 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;
>
> --
> 1.6.5.2
>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>