Or how about an object that can't easily be relocated like, you know, a stack for a kernel thread which also contains the task struct and needs to be moved arou

Or how about an object that can't easily be relocated like, you know, a stack for a kernel thread which also contains the task struct and needs to be moved around between different scheduler queues. But yeah, I understand they took the task struct out of the kernel stack now. Edit: difficult being an understatement, you'd need to solve the halting problem to be able to rewrite any self-referential pointers to stack objects wherever they may be.