Hi Sebastian,

On Tue, 2020-06-09 at 18:38 +0200, Sebastian Andrzej Siewior wrote:

On 2020-06-09 11:21:44 [-0500], Tom Zanussi wrote:

quoted

index 73dae64bfc9c..4f37a6173ab9 100644

--- a/kernel/softirq.c
+++ b/kernel/softirq.c

@@ -947,10 +947,12 @@ static void __tasklet_schedule_common(struct

tasklet_struct *t,
 	 * is locked before adding it to the list.
 	 */
 	if (test_bit(TASKLET_STATE_SCHED, &t->state)) {
+#if defined(CONFIG_SMP)
 		if (test_and_set_bit(TASKLET_STATE_CHAINED, &t->state)) 
{
 			tasklet_unlock(t);
 			return;
 		}
+#endif
 		t->next = NULL;
 		*head->tail = t;
 		head->tail = &(t->next);

@@ -1044,7 +1046,11 @@ static void tasklet_action_common(struct

softirq_action *a,
 again:
 		t->func(t->data);
 
+#if !defined(CONFIG_SMP)
+		while (!tasklet_tryunlock(t)) {
+#else
 		while (cmpxchg(&t->state, TASKLET_STATEF_RC, 0) !=
TASKLET_STATEF_RC) {
+#endif

This is still needed for RT && !SMP

Yes, you're right - I'll change this and repost after testing all
cases.

Thanks,

Tom

quoted

 			/*
 			 * If it got disabled meanwhile, bail out:
 			 */

Sebastian