On Wed, 21 Sep 2016, Matt Fleming wrote: > On Wed, 21 Sep, at 05:58:27PM, Petr Mladek wrote: > > > > I am not sure how the above call chain is realistic. But adding > > WARN_ON() into the scheduler paths is risky in general. > > It's not clear to me why this should be the case. WARN_ON() calls have > existed in the scheduler paths since forever.
Everything which end up in printk within a rq->lock held section has been have been prone to deadlocks for a very long time. Guess why printk_deferred (the former printk_sched) exists. Thanks, tglx