diff --git a/openmp/runtime/src/kmp_lock.cpp b/openmp/runtime/src/kmp_lock.cpp
--- a/openmp/runtime/src/kmp_lock.cpp
+++ b/openmp/runtime/src/kmp_lock.cpp
@@ -1246,6 +1246,9 @@
       if (this_thr->th.th_next_waiting != 0)
         __kmp_dump_queuing_lock(this_thr, gtid, lck, *head_id_p, *tail_id_p);
 #endif
+      // Make sure all updates to thread structures are complete before
+      // assertion check.
+      KMP_MB();
       KMP_DEBUG_ASSERT(this_thr->th.th_next_waiting == 0);
       KA_TRACE(1000, ("__kmp_acquire_queuing_lock: lck:%p, T#%d exiting: after "
                       "waiting on queue\n",