On Wed, May 09, 2018 at 04:33:24PM +0530, Vinayak Menon wrote: > On 5/8/2018 2:31 AM, Johannes Weiner wrote: > > + /* Kick the stats aggregation worker if it's gone to sleep */ > > + if (!delayed_work_pending(&group->clock_work)) > > This causes a crash when the work is scheduled before system_wq is up. In my case when the first > schedule was called from kthreadd. And I had to do this to make it work. > if (keventd_up() && !delayed_work_pending(&group->clock_work)) > > > + schedule_delayed_work(&group->clock_work, MY_LOAD_FREQ); I was trying to figure out how this is possible, and it didn't make sense because we do initialize the system_wq way before kthreadd. Did you by any chance backport this to a pre-4.10 kernel which does not have 3347fa092821 ("workqueue: make workqueue available early during boot") yet? > > +void psi_task_change(struct task_struct *task, u64 now, int clear, int set) > > +{ > > + struct cgroup *cgroup, *parent; > > unused variables They're used in the next patch, I'll fix that up. Thanks