Hello, On Wed, May 10, 2017 at 11:48:17AM -0500, Michael Bringmann wrote: > > On NUMA systems with dynamic processors, the content of the cpumask > may change over time. As new processors are added via DLPAR operations, > workqueues are created for them. This patch ensures that the pools > created for new workqueues will be initialized with a cpumask before > the first worker is created, attached, and woken up. If the mask is > not set up, then the kernel will crash when 'wakeup_process' is unable > to find a valid CPU to which to assign the new worker. > > Signed-off-by: Michael Bringmann <[email protected]> > --- > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index c74bf39..6091069 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -3366,6 +3366,8 @@ static struct worker_pool *get_unbound_pool(const > struct workqueue_attrs *attrs) > copy_workqueue_attrs(pool->attrs, attrs); > pool->node = target_node; > > + cpumask_copy(pool->attrs->cpumask, cpumask_of(smp_processor_id()));
What prevents a cpu getting added right here tho? Maybe the right thing to do is protecting the whole thing with hotplug readlock? Thanks. -- tejun
