diff --git a/trunk/src/utest/srs_utest_rtc.cpp b/trunk/src/utest/srs_utest_rtc.cpp
index b1da5accc..96bf960a6 100644
--- a/trunk/src/utest/srs_utest_rtc.cpp
+++ b/trunk/src/utest/srs_utest_rtc.cpp
@@ -41,6 +41,7 @@ VOID TEST(KernelRTCTest, ConnectionManagerTest)
 {
     srs_error_t err = srs_success;
 
+    // Normal scenario, free object by manager.
     if (true) {
         SrsConnectionManager manager;
         HELPER_EXPECT_SUCCESS(manager.start());
@@ -54,6 +55,38 @@ VOID TEST(KernelRTCTest, ConnectionManagerTest)
         srs_usleep(0); // Switch context for manager to dispose connections.
         EXPECT_EQ(0, manager.size()); EXPECT_TRUE(manager.empty());
     }
+
+    // Coroutine switch context, signal is lost.
+    if (true) {
+        SrsConnectionManager manager;
+        HELPER_EXPECT_SUCCESS(manager.start());
+        EXPECT_EQ(0, manager.size()); EXPECT_TRUE(manager.empty());
+
+        if (true) { // First connection, which will switch context when deleting.
+            MockSrsConnection* conn = new MockSrsConnection();
+            conn->do_switch = true;
+            manager.add(conn);
+            EXPECT_EQ(1, manager.size()); EXPECT_EQ(0, manager.zombies_.size());
+
+            manager.remove(conn); // Remove conn to zombies.
+            EXPECT_EQ(1, manager.size()); EXPECT_EQ(1, manager.zombies_.size());
+
+            srs_usleep(0); // Switch to manager coroutine to try to free zombies.
+            EXPECT_EQ(0, manager.size()); EXPECT_EQ(0, manager.zombies_.size());
+        }
+
+        if (true) { // Now the previous conn switch back to here, and lost the signal.
+            MockSrsConnection* conn = new MockSrsConnection();
+            manager.add(conn);
+            EXPECT_EQ(1, manager.size()); EXPECT_EQ(0, manager.zombies_.size());
+
+            manager.remove(conn); // Remove conn to zombies, signal is lost.
+            EXPECT_EQ(1, manager.size()); EXPECT_EQ(1, manager.zombies_.size());
+
+            srs_usleep(0); // Switch to manager, but no signal is triggered before, so conn will be freed by loop.
+            EXPECT_EQ(0, manager.size()); EXPECT_EQ(0, manager.zombies_.size());
+        }
+    }
 }
 
 VOID TEST(KernelRTCTest, StringDumpHexTest)
diff --git a/trunk/src/utest/srs_utest_service.cpp b/trunk/src/utest/srs_utest_service.cpp
index 7112cc2b0..7cace63cc 100644
--- a/trunk/src/utest/srs_utest_service.cpp
+++ b/trunk/src/utest/srs_utest_service.cpp
@@ -44,10 +44,14 @@ using namespace std;
 
 MockSrsConnection::MockSrsConnection()
 {
+    do_switch = false;
 }
 
 MockSrsConnection::~MockSrsConnection()
 {
+    if (do_switch) {
+        srs_usleep(0);
+    }
 }
 
 std::string MockSrsConnection::remote_ip()
diff --git a/trunk/src/utest/srs_utest_service.hpp b/trunk/src/utest/srs_utest_service.hpp
index 84aa9be7e..d60254a2b 100644
--- a/trunk/src/utest/srs_utest_service.hpp
+++ b/trunk/src/utest/srs_utest_service.hpp
@@ -34,6 +34,9 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 class MockSrsConnection : public ISrsConnection
 {
+public:
+    // Whether switch the coroutine context when free the object, for special case test.
+    bool do_switch;
 public:
     MockSrsConnection();
     virtual ~MockSrsConnection();