Re: Q: perf_install_in_context/perf_event_enable are racy?

From: Oleg Nesterov
Date: Thu Jan 27 2011 - 11:00:15 EST


On 01/27, Peter Zijlstra wrote:
>
> On Wed, 2011-01-26 at 22:33 +0100, Oleg Nesterov wrote:
> >
> > This is what I had in mind initially but I didn't dare to add the
> > new member into rq, it is only needed for perf.
>
> Right, but its a weakness in the task_oncpu_function_call()
> implementation, wouldn't any user run into this problem eventually?

I think that other users are fine, they do not try to change ctx.

OTOH, probably your change in task_oncpu_function_call() makes sense
anyway, this way func() can never have some other subtle problems
witht context_switch in progress.

Oleg.

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