diff --git a/elements/etherswitch/etherswitch.cc b/elements/etherswitch/etherswitch.cc
index 6f83f4f5ab..4983b405a8 100644
--- a/elements/etherswitch/etherswitch.cc
+++ b/elements/etherswitch/etherswitch.cc
@@ -62,7 +62,8 @@ EtherSwitch::broadcast(int source, Packet *p)
   for (int i = 0; i < n && w > 0; i++) {
     if (pfr.bv[i]) {
       Packet *pp = (w > 1 ? p->clone() : p);
-      output(i).push(pp);
+      if (pp)
+        output(i).push(pp);
       w--;
     }
   }
diff --git a/elements/icmp/icmpsendpings.cc b/elements/icmp/icmpsendpings.cc
index 38eb592130..8facdc7ff5 100644
--- a/elements/icmp/icmpsendpings.cc
+++ b/elements/icmp/icmpsendpings.cc
@@ -154,7 +154,7 @@ ICMPPingSource::make_packet(WritablePacket *q)
     q->set_ip_header(nip, sizeof(click_ip));
     q->timestamp_anno().assign_now();
 
-    if (_receiver)
+    if (q && _receiver)
 	_receiver->send_timestamp[icp->icmp_sequence] = q->timestamp_anno();
 
     return q;
diff --git a/include/click/hashtable.hh b/include/click/hashtable.hh
index 05814946c3..9de0cbfd0d 100644
--- a/include/click/hashtable.hh
+++ b/include/click/hashtable.hh
@@ -951,7 +951,9 @@ template <typename T>
 typename HashTable<T>::value_type &
 HashTable<T>::operator[](key_const_reference key)
 {
-    return *find_insert(key);
+    HashTable_iterator<T> i = find_insert(key);
+    assert(i.get());
+    return *i;
 }
 
 template <typename T>
diff --git a/lib/fromfile.cc b/lib/fromfile.cc
index e0bb6dd24d..57217f13ad 100644
--- a/lib/fromfile.cc
+++ b/lib/fromfile.cc
@@ -157,6 +157,11 @@ FromFile::read_buffer_mmap(ErrorHandler *errh)
 	return error(errh, "mmap: %s", strerror(errno));
 
     _data_packet = Packet::make((unsigned char *)mmap_data, _len, munmap_destructor, 0);
+    if (!_data_packet) {
+        munmap_destructor((unsigned char *)mmap_data, _len, NULL);
+        return error(errh, "Packet::make failed");
+    }
+
     _buffer = _data_packet->data();
     _file_offset = _mmap_off;
     _mmap_off += _len;