Re: [patch 3/14] x86, ptrace, bts: stop bts tracing early in do_exit

[Andi Kleen]

> > > ds_release_bts(struct bts_tracer *tracer)
> > > {
> > > 	struct task_struct *task =
> > > 		tracer->ds.context->task;
> > >
> > > 	do {
> > > 		set_task_state(task, TASK_UNINTERRUPTIBLE);
> > Oh, this is not right,
>
> Agreed.
>
> I wonder if it is ever safe to change another task's state.
> There's a lot of code that sets the task state seemingly
> unprotected - but always for current.

It should be safe when you can guarantee that the other task is stopped
(as in ptrace) and you protect against yourself (only a single
external writer)

-Andi
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