diff --git a/src/devices/wifi/dca-txop.cc b/src/devices/wifi/dca-txop.cc
index 5701e1bc3..1630da924 100644
--- a/src/devices/wifi/dca-txop.cc
+++ b/src/devices/wifi/dca-txop.cc
@@ -37,7 +37,7 @@
 NS_LOG_COMPONENT_DEFINE ("DcaTxop");
 
 #undef NS_LOG_APPEND_CONTEXT
-#define NS_LOG_APPEND_CONTEXT std::clog << "[mac=" << m_low->GetAddress () << "] ";
+#define NS_LOG_APPEND_CONTEXT if (m_low != 0) {std::clog << "[mac=" << m_low->GetAddress () << "] ";}
 
 namespace ns3 {
 
diff --git a/src/devices/wifi/edca-txop-n.cc b/src/devices/wifi/edca-txop-n.cc
index f703bc79d..91d9a6f38 100644
--- a/src/devices/wifi/edca-txop-n.cc
+++ b/src/devices/wifi/edca-txop-n.cc
@@ -38,7 +38,7 @@
 NS_LOG_COMPONENT_DEFINE ("EdcaTxopN");
 
 #undef NS_LOG_APPEND_CONTEXT
-#define NS_LOG_APPEND_CONTEXT std::clog << "[mac=" << m_low->GetAddress () << "] ";
+#define NS_LOG_APPEND_CONTEXT if (m_low != 0) {std::clog << "[mac=" << m_low->GetAddress () << "] ";}
 
 namespace ns3 {