Re: the select system call's implementation may have some bug inpreempt kernel mode

From: Thomas Gleixner
Date: Fri Oct 09 2009 - 03:24:16 EST


On Fri, 9 Oct 2009, wu Jianfeng wrote:

> > Right, but that does not cause the task to be scheduled out for ever.
>
> I don't know why ???
> the process state is TASK_INTERRUPTIBLE, and was scheduled out.
>
> if no one wake up it or any signals received, it will sleep for ever.
> The process does't entered any file's wait queue at that point, so I
> am sure no one will wake up it.
>
> Am i right?

No. Did you actually read, what I wrote further down ?

> > When the task is scheduled out at that point, it is not
> > deactivated. It is preempted, which means it stays on the run queue
> > despite of the TASK_INTERRUPTIBLE state and is scheduled back in later
> > on.

Thanks,

tglx
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