title: using pstack to print all threads stacktrace
body: <p>I am trying to use pstack to print the stacktrace of all threads of specific process, but I get only the main thread.</p>
  
  <p>According to the pstack description:<br>
  <em>pstack - print a stack trace of a running process<br>
  ...<br>
  If the process is part of a thread group, then pstack will print out a stack trace for each of the threads in the group.</em></p>
  
  <p>I used gdb to attach to the process and verified that there are more threads. I run pstack with one of threads id, and got the requested result.<br>
  <em>[I also used ps -j and saw other <strong>processes</strong> with the same group id, but I don't think it is relevant]</em></p>
  
  <p>I read related pstack questions, but didn't see anything that can help me. Also searched google, but didn't see anyone asking about it.</p>
  
  <p>Thanks</p>
  
  <hr>
  
  <p>I didn't notice that 
  "For thread information to be dumped, you have to use the debug-aware  version  of  the  LinuxThreads libpthread.so  library."</p>