diff --git a/src/mesa/main/debug_output.c b/src/mesa/main/debug_output.c
index 6527aea5771..d47756c9b50 100644
--- a/src/mesa/main/debug_output.c
+++ b/src/mesa/main/debug_output.c
@@ -193,7 +193,8 @@ void
 _mesa_debug_get_id(GLuint *id)
 {
    if (!(*id)) {
-      *id = p_atomic_inc_return(&PrevDynamicID);
+      /* Don't update *id if we raced with some other thread. */
+      p_atomic_cmpxchg(id, 0, p_atomic_inc_return(&PrevDynamicID));
    }
 }