From bebfc360da574a08a742b2f974618d14ea00ad13 Mon Sep 17 00:00:00 2001
From: Ruize Tang <1466040111@qq.com>
Date: Mon, 9 Sep 2024 16:18:03 +0800
Subject: [PATCH] Fix lost-wakeup in RwMutexUpgradeableGuard_.drop()

---
 ostd/src/sync/rwmutex.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ostd/src/sync/rwmutex.rs b/ostd/src/sync/rwmutex.rs
index 31b34bb5f..d5fc9a843 100644
--- a/ostd/src/sync/rwmutex.rs
+++ b/ostd/src/sync/rwmutex.rs
@@ -377,7 +377,7 @@ impl<T: ?Sized, R: Deref<Target = RwMutex<T>>> Deref for RwMutexUpgradeableGuard
 impl<T: ?Sized, R: Deref<Target = RwMutex<T>>> Drop for RwMutexUpgradeableGuard_<T, R> {
     fn drop(&mut self) {
         let res = self.inner.lock.fetch_sub(UPGRADEABLE_READER, Release);
-        if res == 0 {
+        if res == UPGRADEABLE_READER {
             self.inner.queue.wake_all();
         }
     }