On Mon, 2013-07-01 at 21:36 +0200, Oleg Nesterov wrote:
> On 07/01, Steven Rostedt wrote:
> >
> > On Thu, 2013-06-20 at 19:38 +0200, Oleg Nesterov wrote:
> >
> > > -static int
> > > -trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file
> > > *file)
> > > +static struct event_file_link *
> > > +find_event_file_link(struct trace_probe *tp, struct ftrace_event_file
> > > *file)
> > > {
> > > - struct ftrace_event_file **files;
> > > - int i;
> > > + struct event_file_link *link;
> > >
> > > - /*
> > > - * Since all tp->files updater is protected by probe_enable_lock,
> > > - * we don't need to lock an rcu_read_lock.
> > > - */
> > > - files = rcu_dereference_raw(tp->files);
> > > - if (files) {
> > > - for (i = 0; files[i]; i++)
> > > - if (files[i] == file)
> > > - return i;
> > > - }
> > > + list_for_each_entry(link, &tp->files, list)
> > > + if (link->file == file)
> > > + return link;
> >
> > Shouldn't that be list_for_each_entry_rcu()?
>
> No.
>
> This is the writer which modifies the list. enable/disable_trace_probe
> should be serialized wrt each other / itself anyway, otherwise they are
> buggy in any case.
Ah OK, I missed the readers of kprobe*_trace_func() and was confused by
the other rcu usage. Nevermind.
-- Steve
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