MLK.RET.MUST

Memory leak

The MLK.RET.MUST issue is reported when allocated memory is returned from a function, but is not assigned to any variable. The allocated memory is lost at this point.

Vulnerability and risk

Memory leaks cause the application to consume additional memory. This reduces the amount of memory available to other applications and eventually causes the operating system to start paging, slowing the system down. In critical cases, the application will reach overall memory limits, which may result in application crashes.

Vulnerable code example

Copy 
  void* alloc_data()
  {
    return malloc(10);
  }

  void foo()
  {
    alloc_data();
  }

Klocwork produces a memory leak report indicating that dynamic memory allocated through function 'alloc_data' is lost at line 8.

Fixed code example

Copy 
  void* alloc_data()
  {
    return malloc(10);
  }

  void foo()
  {
    void* ptr = alloc_data();
    free(ptr);
  }

External guidance