Re: [PATCH 1/3] futex_find_get_task: remove an obscure EXIT_ZOMBIE check

[Ingo Molnar <mingo@elte.hu>]

* Oleg Nesterov <oleg@tv-sign.ru> wrote:

> (Compile tested).
> 
> futex_find_get_task:
> 
> 	if (p->state == EXIT_ZOMBIE || p->exit_state == EXIT_ZOMBIE)
> 		return NULL;
> 
> I can't understand this. First, p->state can't be EXIT_ZOMBIE. The 
> ->exit_state check looks strange too. Sub-threads or tasks whose 
> ->parent ignores SIGCHLD go directly to EXIT_DEAD state (I am ignoring 
> a ptrace case). Why EXIT_DEAD tasks should be ok? Yes, EXIT_ZOMBIE is 
> more important (a task may stay zombie for a long time), but this 
> doesn't mean we should explicitely ignore other EXIT_XXX states.
> 
> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>

i believe this is a remnant of older times when EXIT_ZOMBIE was 
introduced. We cloned that into the -rt tree, but then exit-state got 
cleaned up (by you) upstream and that cleanup didnt propagate into the 
-rt tree. Andrew: i think this is a must-have fix for v2.6.18.

Acked-by: Ingo Molnar <mingo@elte.hu>

	Ingo