Re: [RFC][PATCH 3/4] tracing/kprobes: Fail to unregister if probe event files are open

[Oleg Nesterov <oleg@redhat.com>]

On 08/01, Oleg Nesterov wrote:
>
> And just in case. I believe that the patch is fine.
>
> Just one off-topic note,

Forgot to mention,

> > @@ -632,7 +635,9 @@ static int release_all_trace_probes(void)
> >  	/* TODO: Use batch unregistration */
> >  	while (!list_empty(&probe_list)) {
> >  		tp = list_entry(probe_list.next, struct trace_probe, list);
> > -		unregister_trace_probe(tp);
> > +		ret = unregister_trace_probe(tp);
> > +		if (ret)
> > +			goto end;
> >  		free_trace_probe(tp);
> >  	}
>
> This obviously breaks all-or-nothing semantics (I mean, this breaks
> the intent, the current code is buggy).
>
> I think we can't avoid this, and I hope this is fine. But then perhaps
> we should simply remove the "list_for_each_entry" check above?

And, of course, turn this "while (!list_empty())" into list_for_each_safe().

But again, this is almost off-topic and we can do this later.

Oleg.