On Mon, Nov 16 2020 at 13:10, Peter Zijlstra wrote: > Any which way around; here's a proper patch... > > --- > > Subject: rcu: Allow rcu_irq_enter_check_tick() from NMI > From: Peter Zijlstra <[email protected]> > Date: Mon Nov 16 12:54:56 CET 2020 > > Eugenio managed to tickle #PF from NMI context which resulted in > hitting a WARN in RCU through irqentry_enter() -> > __rcu_irq_enter_check_tick(). > > However, this situation is perfectly sane and does not warrant an > WARN. The #PF will (necessarily) be atomic and not require messing > with the tick state, so early return is correct. > > Fixes: aaf2bc50df1f ("rcu: Abstract out rcu_irq_enter_check_tick() from > rcu_nmi_enter()") > Reported-by: "Eugenio Pérez" <[email protected]> > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > Reviewed-by: Andy Lutomirski <[email protected]> > Reviewed-by: Paul E. McKenney <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
