Re: [PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way

[Oleg Nesterov]

On 05/11, Linus Torvalds wrote:
>
> On Fri, 11 May 2007, Rafael J. Wysocki wrote:
> > 
> > Therefore, by taking the task_lock() here we make sure that the condition
> > is alyways false when we check it for kernel threads.
> 
> Why *test* it then and return anything?
> 
> Why not just doa "task_lock(p); task_unlock(p);" with no return value? 

because we should not freeze a kernel thread at FREEZER_USER_SPACE stage?

without task_lock() we can see "p->mm != NULL" but not PF_BORROWED_MM.

Oleg.

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