diff --git a/cmds/lshal/Lshal.cpp b/cmds/lshal/Lshal.cpp
index 6115da7..5cdcb23 100644
--- a/cmds/lshal/Lshal.cpp
+++ b/cmds/lshal/Lshal.cpp
@@ -232,6 +232,11 @@
         return static_cast<HelpCommand*>(help)->usageOfCommand(mCommand);
     }
 
+    // After Lshal::main() finishes, caller may call _exit(), causing debug
+    // information to prematurely ends. Hence flush().
+    err().flush();
+    out().flush();
+
     return status;
 }
 
diff --git a/cmds/lshal/NullableOStream.h b/cmds/lshal/NullableOStream.h
index 7cffcf8..1576486 100644
--- a/cmds/lshal/NullableOStream.h
+++ b/cmds/lshal/NullableOStream.h
@@ -59,6 +59,11 @@
     operator bool() const { // NOLINT(google-explicit-constructor)
         return mOs != nullptr;
     }
+    void flush() {
+        if (mOs) {
+            mOs->flush();
+        }
+    }
 private:
     template<typename>
     friend class NullableOStream;