> On Jun 12, 2020, at 12:25 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > > "Paul E. McKenney" <paulmck@xxxxxxxxxx> writes: >>> On Fri, Jun 12, 2020 at 10:49:53AM -0700, Paul E. McKenney wrote: >>> I will therefore address this issue in a follow-on patch. >> >> I should add that -your- patch from yesterday did -not- cause this >> problem, in case that is of interest. > > So I still can add it back and amend the changelog and comment: > > Change the condition from !rcu_is_watching() to is_idle_task(current) || > rcu_is_watching() which enforces that interrupts in the idle task > unconditionally invoke rcu_irq_enter() independent of the RCU state. For > most scenarios is_idle_task() would be sufficient but Task RCU needs it > according to Paul. > > Can you easily get a call trace for a case where the system is fully booted, is_idle_task returns false, and rcu_is_watching() also returns false?
