Locked the entire Backtrace's constructor. It may solve the segfault in the ::backtrace_symbols

common/exception/Backtrace.cpp

@@ -117,7 +117,6 @@ cta::exception::Backtrace::Backtrace(bool fake): m_trace() {
   void * array[200];
   g_lock.lock();  
   size_t depth = ::backtrace(array, sizeof(array)/sizeof(void*));
-  g_lock.unlock();
   char ** strings = ::backtrace_symbols(array, depth);
 
   if (!strings)
@@ -158,6 +157,7 @@ cta::exception::Backtrace::Backtrace(bool fake): m_trace() {
     }
     free (strings);
   }
+  g_lock.unlock();
 }
 
 /* Implementation of the singleton lock */