From: Frederic Weisbecker <frederic@xxxxxxxxxx> commit 54b7429efffc99e845ba9381bee3244f012a06c2 upstream. Deferred wakeup of rcuog kthreads upon RCU idle mode entry is going to be handled differently whether initiated by idle, user or guest. Prepare with pulling that control up to rcu_eqs_enter() callers. Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20210131230548.32970-2-frederic@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/rcu/tree.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -636,7 +636,6 @@ static noinstr void rcu_eqs_enter(bool u trace_rcu_dyntick(TPS("Start"), rdp->dynticks_nesting, 0, atomic_read(&rdp->dynticks)); WARN_ON_ONCE(IS_ENABLED(CONFIG_RCU_EQS_DEBUG) && !user && !is_idle_task(current)); rdp = this_cpu_ptr(&rcu_data); - do_nocb_deferred_wakeup(rdp); rcu_prepare_for_idle(); rcu_preempt_deferred_qs(current); @@ -664,7 +663,10 @@ static noinstr void rcu_eqs_enter(bool u */ void rcu_idle_enter(void) { + struct rcu_data *rdp = this_cpu_ptr(&rcu_data); + lockdep_assert_irqs_disabled(); + do_nocb_deferred_wakeup(rdp); rcu_eqs_enter(false); } EXPORT_SYMBOL_GPL(rcu_idle_enter); @@ -683,7 +685,14 @@ EXPORT_SYMBOL_GPL(rcu_idle_enter); */ noinstr void rcu_user_enter(void) { + struct rcu_data *rdp = this_cpu_ptr(&rcu_data); + lockdep_assert_irqs_disabled(); + + instrumentation_begin(); + do_nocb_deferred_wakeup(rdp); + instrumentation_end(); + rcu_eqs_enter(true); } #endif /* CONFIG_NO_HZ_FULL */
