From 3460e289851112f1007cf75ab10806ba6b1cbf2c Mon Sep 17 00:00:00 2001
From: chao an <anchao.archer@bytedance.com>
Date: Tue, 27 Oct 2026 17:06:40 +0800
Subject: [PATCH] sched/event: Skip post processing without waiters

Avoid preparing wakeup state when posting events to an empty wait list.
The event bits are still updated before returning so future waiters observe
the posted state.

Signed-off-by: chao an <anchao.archer@bytedance.com>
---
 sched/event/event_post.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/sched/event/event_post.c b/sched/event/event_post.c
index 6b6cf6ec0ad10..5a8a6f5286de0 100644
--- a/sched/event/event_post.c
+++ b/sched/event/event_post.c
@@ -86,9 +86,15 @@ int nxevent_post(FAR nxevent_t *event, nxevent_mask_t events,
       event->events |= events ? events : ~0;
     }
 
+  waitlist = EVENT_WAITLIST(event);
+  if (dq_empty(waitlist))
+    {
+      leave_critical_section(flags);
+      return OK;
+    }
+
   postall = ((eflags & NXEVENT_POST_ALL) != 0);
   rtcb    = this_task();
-  waitlist = EVENT_WAITLIST(event);
 
   dq_for_every_safe(waitlist, entry, tmp)
     {