Re: [PATCH 2/8] kernel/fork: Duplicate task_struct before stack allocation.

[Andy Lutomirski <luto@xxxxxxxxxx>]

On 1/25/22 07:26, Sebastian Andrzej Siewior wrote:
> alloc_thread_stack_node() already populates the task_struct::stack
> member except on IA64. The stack pointer is saved and populated again
> because IA64 needs it and arch_dup_task_struct() overwrites it.

I understand the problem, I think.

> Allocate thread's stack after task_struct has been duplicated as a
> preparation.

But I don't understand this.  How does this patch relate to the problem?

Also, you appear to be missing a change to the free_stack and free_tsk 
code at the end of dup_task_struct().