diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index acbe298b310..c2f86a9d367 100644
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -181,7 +181,7 @@ private:
   std::atomic<packed<dwarf_unit_type, 1>> m_unit_type {(dwarf_unit_type)0};
 
   /* The language of this CU.  */
-  packed<language, LANGUAGE_BYTES> m_lang = language_unknown;
+  std::atomic<packed<language, LANGUAGE_BYTES>> m_lang {language_unknown};
 
 public:
   /* True if this CU has been scanned by the indexer; false if
@@ -351,21 +351,25 @@ public:
 
   enum language lang (bool strict_p = true) const
   {
+    enum language l = m_lang.load ();
     if (strict_p)
-      gdb_assert (m_lang != language_unknown);
-    return m_lang;
+      gdb_assert (l != language_unknown);
+    return l;
   }
 
   void set_lang (enum language lang)
   {
     if (unit_type () == DW_UT_partial)
       return;
-    if (m_lang == language_unknown)
-      /* Set if not set already.  */
-      m_lang = lang;
-    else
-      /* If already set, verify that it's the same value.  */
-      gdb_assert (m_lang == lang);
+    /* Set if not set already.  */
+    packed<language, LANGUAGE_BYTES> nope = language_unknown;
+    if (m_lang.compare_exchange_strong (nope, lang))
+      return;
+    /* If already set, verify that it's the same value.  */
+    nope = lang;
+    if (m_lang.compare_exchange_strong (nope, lang))
+      return;
+    gdb_assert_not_reached ();
   }
 
   /* Free any cached file names.  */