Re: [PATCH 2/3] Make suspend possible with a traced process at a breakpoint

[Pavel Machek <pavel@ucw.cz>]

Hi!

> It should be possible to suspend, either to RAM or to disk, if there's a
> traced process that has just reached a breakpoint.  However, this is a special
> case, because its parent process might have been frozen already and then
> we are unable to deliver the "freeze" signal to the traced process.  If this
> happens, it's better to cancel the freezing of the traced process.

Thanks for debugging this.

> @@ -85,6 +97,10 @@ int freeze_processes(void)
>  				continue;
>  			if (frozen(p))
>  				continue;
> +			if (p->state == TASK_TRACED && frozen(p->parent)) {
> +				cancel_freezing(p);
> +				continue;
> +			}

Could we just add line to freezeable, like this?

...no, this is probably racy, because freezeable() should not change
while we are thawing other processes... I was hoping for one-liner...

diff --git a/kernel/power/process.c b/kernel/power/process.c
index b2a5f67..13dceb8 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -26,6 +26,7 @@ static inline int freezeable(struct task
 	    (p->flags & PF_NOFREEZE) ||
 	    (p->exit_state == EXIT_ZOMBIE) ||
 	    (p->exit_state == EXIT_DEAD) ||
+	    ((p->exit_state == TASK_TRACED) && frozen(p->parent)) ||
 	    (p->state == TASK_STOPPED))
 		return 0;
 	return 1;

...okay, so ACK on your patch.
								Pavel
-- 
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