diff --git a/libraries/AP_HAL_SITL/Semaphores.cpp b/libraries/AP_HAL_SITL/Semaphores.cpp
index 0067fd9c148..b68ab31e86a 100644
--- a/libraries/AP_HAL_SITL/Semaphores.cpp
+++ b/libraries/AP_HAL_SITL/Semaphores.cpp
@@ -22,12 +22,12 @@ Semaphore::Semaphore()
 bool Semaphore::give()
 {
     take_count--;
-    if (pthread_mutex_unlock(&_lock) != 0) {
-        AP_HAL::panic("Bad semaphore usage");
-    }
     if (take_count == 0) {
         owner = (pthread_t)-1;
     }
+    if (pthread_mutex_unlock(&_lock) != 0) {
+        AP_HAL::panic("Bad semaphore usage");
+    }
     return true;
 }