rcu/exp: Fix check for idle context in rcu_exp_handler

For PREEMPT_RCU, the rcu_exp_handler() function checks
whether the current CPU is in idle, by calling
rcu_dynticks_curr_cpu_in_eqs(). However, rcu_exp_handler()
is called in IPI handler context. So, it should be checking
the idle context using rcu_is_cpu_rrupt_from_idle(). Fix this
by using rcu_is_cpu_rrupt_from_idle() instead of
rcu_dynticks_curr_cpu_in_eqs(). Non-preempt configuration
already uses the correct check.

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 237a79989abae0fd169b436e97ea6edd39d63ec5..1568c8ef185b2badccdf07560a397fd9739ad2b7 100644 (file)
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -656,7 +656,7 @@ static void rcu_exp_handler(void *unused)
         */
        if (!depth) {
                if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||
-                   rcu_dynticks_curr_cpu_in_eqs()) {
+                   rcu_is_cpu_rrupt_from_idle()) {
                        rcu_report_exp_rdp(rdp);
                } else {
                        WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);