malloctrace would crash if you asked it for more topAllocators than there were

diff --git a/pdns/malloctrace.cc b/pdns/malloctrace.cc
index 750782c78a96345bd3ff41681897ec8f268a5fe3..e58add9b62dd9bcec3f7bb1dba26050d736e0c95 100644 (file)
--- a/pdns/malloctrace.cc
+++ b/pdns/malloctrace.cc
@@ -90,7 +90,9 @@ MallocTracer::allocators_t MallocTracer::topAllocators(int num)
          const allocators_t::value_type& b) {
         return a.first.count < b.first.count;
        });
-  if(num > 0)
+  if((unsigned int)num > ret.size())
+    ret.clear();
+  else if(num > 0)
     ret.erase(ret.begin(), ret.begin() + (ret.size() - num));
   l_active=false;
   return ret;