diff --git a/webrtc/system_wrappers/source/event_posix.cc b/webrtc/system_wrappers/source/event_posix.cc
index eeef8095d7..907409bd59 100644
--- a/webrtc/system_wrappers/source/event_posix.cc
+++ b/webrtc/system_wrappers/source/event_posix.cc
@@ -18,6 +18,8 @@
 #include <sys/time.h>
 #include <unistd.h>
 
+#include "webrtc/base/checks.h"
+
 namespace webrtc {
 
 const long int E6 = 1000000;
@@ -146,6 +148,9 @@ EventTypeWrapper EventPosix::Wait(unsigned long timeout) {
     }
   }
 
+  if (ret_val == 0)
+    CHECK(state_ == kUp);
+
   state_ = kDown;
   pthread_mutex_unlock(&mutex_);