title: "thread apply all bt full" gives blank in GDB
body: <p>I was trying to debug a multi-threaded process on a Linux server running Slackware 12 using GDB 6.6.</p>
  
  <p>Once I attach and issue the command "thread apply all bt full" it comes back with nothing ( back on to the gdb prompt ).</p>
  
  <p>Any idea why this happens?</p>