On Tue, Jul 2, 2024 at 9:11 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote:
>
> On Tue, Jul 02, 2024 at 03:04:08PM +0200, Peter Zijlstra wrote:
> > On Mon, Jul 01, 2024 at 06:41:07PM +0200, Jiri Olsa wrote:
> >
> > > +static void
> > > +uprobe_consumer_account(struct uprobe *uprobe, struct uprobe_consumer *uc)
> > > +{
> > > + static unsigned int session_id;
> > > +
> > > + if (uc->session) {
> > > + uprobe->sessions_cnt++;
> > > + uc->session_id = ++session_id ?: ++session_id;
> > > + }
> > > +}
> >
> > The way I understand this code, you create a consumer every time you do
> > uprobe_register() and unregister makes it go away.
> >
> > Now, register one, then 4g-1 times register+unregister, then register
> > again.
> >
> > The above seems to then result in two consumers with the same
> > session_id, which leads to trouble.
> >
> > Hmm?
>
> ugh true.. will make it u64 :)
>
> I think we could store uprobe_consumer pointer+ref in session_consumer,
> and that would make the unregister path more interesting.. will check
More interesting how? It's actually a great idea, uprobe_consumer
pointer itself is a unique ID and 64-bit. We can still use lowest bit
for RC (see my other reply).
>
> thanks,
> jirka
