On Wed, Jun 15, 2016 at 02:46:10PM -0700, Paul E. McKenney wrote: > Currently, if the very first call to call_rcu_tasks() has irqs disabled, > it will create the rcu_tasks_kthread with irqs disabled, which will > result in a splat in the memory allocator, which kthread_run() invokes > with the expectation that irqs are enabled. > > This commit fixes this problem by deferring kthread creation if called > with irqs disabled. The first call to call_rcu_tasks() that has irqs > enabled will create the kthread. > > This bug was detected by rcutorture changes that were motivated by > Iftekhar Ahmed's mutation-testing efforts. > > Signed-off-by: Paul E. McKenney <[email protected]>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 218f8e83db73..4a3b279beb42 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -2175,7 +2175,7 @@ void task_numa_free(struct task_struct *p) > > grp->nr_tasks--; > spin_unlock_irqrestore(&grp->lock, flags); > - RCU_INIT_POINTER(p->numa_group, NULL); > + rcu_assign_pointer(p->numa_group, NULL); > put_numa_group(grp); > } This seems entirely unrelated; albeit desired given that other patch.
