Re: proc race (was: Re: HIGH MEMORY access)

[Alan Cox]

> do_exit() calls __exit_mm() before task_lock(), and __exit_mm() sets
> tsk->mm to NULL before acquiring task_lock().
> 
> How should we fix that? With start_lazy_tlb() [kernel/exit.c], it's
> possible to construct all kind of weird races.

I think _exit_mm() needs to swap the mm a pointer to the task 0 mm, instead
of NULL. Then all the weird cases go away