title: Do threads/processes have to disable interrupts while executing a critical section
body: <p>Let us consider a scenario:-</p>
  
  <p>A Kernel thread acquires a lock and is in the middle of a critical section when an interrupt occurs.
  The interrupt handler runs and arrives at the same critical section and tries to acquire lock and go to sleep.</p>
  
  <p>Can this happen or are interrupts disabled during a critical section ?
  what steps are taken to to avoid it ?</p>
  
  <pre><code>// Some Code
   Acquire_lock()
  
  Critical section   //Interrupt occurs and arrives to acquire the same lock.
  
  Disable_lock()
  </code></pre>