title: What exactly SIG_DFL do?
body: <p>What exactly SIG_DFL (defaut handler for signals) does? I'm interested in debugging SIGTSTP. It misbehaves slightly under weird conditions. I have suspicion it is doing something strange if one the threads is in the TASK_ININTERRUPTBLE state.</p>
  
  <p>Where is SIG_DFL source code? Libc?</p>
  
  <p>Thanks.</p>