-a/src/utils/execmd.cpp
+b/src/utils/execmd.cpp
 ...
 private:
     string        *m_output;
     ExecCmdAdvise *m_advise;
 };
+// The netcon selectloop that doexec() uses for reading/writing would
+// be complicated to render thread-safe. Use locking to ensure only
+// one thread in there
+class ExecLocking {
+public:
+    pthread_mutex_t m_mutex;
+    ExecLocking()
+    {
+  pthread_mutex_init(&m_mutex, 0);
+    }
+};
+ExecLocking o_lock;
+class ExecLocker {
+public:
+    ExecLocker()
+    {
+  pthread_mutex_lock(&o_lock.m_mutex);
+    }
+    ~ExecLocker()
+    {
+  pthread_mutex_unlock(&o_lock.m_mutex);
+    }
+};
 int ExecCmd::doexec(const string &cmd, const list<string>& args,
             const string *input, string *output)
+{
     if (startExec(cmd, args, input != 0, output != 0) < 0) {
     return -1;
+    }
     // Cleanup in case we return early
     ExecCmdRsrc e(this);
+    // Only one thread allowed in here...
+    ExecLocker locker;
     int ret = 0;
     if (input || output) {
         // Setup output
     if (output) {