Re: [PATCH] Fix posix-cpu-timer breakage caused by stale p->last_ran value

[Ingo Molnar <mingo@elte.hu>]

* Thomas Gleixner <tglx@linutronix.de> wrote:

> The problem is that the p->last_ran value is not updated after a 
> context switch. So a subsequent call to current_sched_time() 
> calculates with a stale p->last_ran value, i.e. accounts the full 
> time, which the task was scheduled away.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

>  	sched_info_switch(prev, next);
>  	if (likely(prev != next)) {
> -		next->timestamp = now;
> +		next->timestamp = next->last_ran = now;

ouch! nice catch. Also for v2.6.20.2 i think. 2.6.19 should be 
unaffected.

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

	Ingo