From feb0bdd159a8d79b576db68a4bb8562cb33aea63 Mon Sep 17 00:00:00 2001
From: Sean Cross <sean@xobs.io>
Date: Sun, 24 Dec 2023 17:23:30 +0800
Subject: [PATCH] xous: thread_parking: fix logic on wakeup race

When waking up a thread and there's a race condition, the logic may be
inverted. Or the thread may time out, in which case there is no thread
to wake up.

Signed-off-by: Sean Cross <sean@xobs.io>
---
 library/std/src/sys/xous/thread_parking.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/library/std/src/sys/xous/thread_parking.rs b/library/std/src/sys/xous/thread_parking.rs
index ec1b6d8c79968..872a4f112d551 100644
--- a/library/std/src/sys/xous/thread_parking.rs
+++ b/library/std/src/sys/xous/thread_parking.rs
@@ -83,7 +83,8 @@ impl Parker {
             TicktimerScalar::NotifyCondition(self.index(), 1).into(),
         )
         .expect("failed to send NotifyCondition command")[0]
-            == 1
+            != 1
+            && self.state.load(Acquire) != EMPTY
         {
             // The target thread hasn't yet hit the `WaitForCondition` call.
             // Yield to let the target thread run some more.