title: Clone() system call in linux
body: <p>What happens when I call clone system call by passing 0 as the stack_start? 
  According to manual pages on clone it should return <code>-EINVAL</code>, but when I do that, it is showing <code>SIGSEGV (11)</code> error.</p>
  
  <pre><code>clone(func,NULL,0,args);
  </code></pre>
  
  <p>should return -EINVAL, but its failing with <code>SIGSEGV</code></p>