Re: [PATCH] block: fix a crash in do_task_dead()

[Gaurav Kohli]

> > > +
> >
> > Hi Peter, Jen,
> >
> > As we are not taking pi_lock here , is there possibility of same task dead
> > call comes as this point of time for current thread, bcoz of which we have
> > seen earlier issue after this commit 0619317ff8ba
> > [T114538]  do_task_dead+0xf0/0xf8
> > [T114538]  do_exit+0xd5c/0x10fc
> > [T114538]  do_group_exit+0xf4/0x110
> > [T114538]  get_signal+0x280/0xdd8
> > [T114538]  do_notify_resume+0x720/0x968
> > [T114538]  work_pending+0x8/0x10
> >
> > Is there a chance of TASK_DEAD set at this point of time?
>
> In this case try_to_wake_up(current, TASK_NORMAL) will do nothing, see the
> if (!(p->state & state)) above.
>
> See also the comment about set_special_state() above. It disables irqs and
> this is enough to ensure that try_to_wake_up(current) from irq can't race
> with set_special_state(TASK_DEAD).

Thanks Oleg,

I missed that part(both thread and interrupt is in same core only), So 
that situation would never come.
> Oleg.

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