On 09/13, Jiri Olsa wrote:
>
> On Thu, Sep 12, 2024 at 06:35:39PM +0200, Oleg Nesterov wrote:
> > >   list_for_each_entry_srcu(uc, &uprobe->consumers, cons_node,
> > >                            srcu_read_lock_held(&uprobes_srcu)) {
> > > +         /*
> > > +          * If we don't find return consumer, it means uprobe consumer
> > > +          * was added after we hit uprobe and return consumer did not
> > > +          * get registered in which case we call the ret_handler only
> > > +          * if it's not session consumer.
> > > +          */
> > > +         ric = return_consumer_find(ri, &iter, uc->id);
> > > +         if (!ric && uc->session)
> > > +                 continue;
> > >           if (uc->ret_handler)
> > > -                 uc->ret_handler(uc, ri->func, regs);
> > > +                 uc->ret_handler(uc, ri->func, regs, ric ? &ric->cookie 
> > > : NULL);
> >
> > So why do we need the new uc->session member and the uc->session above ?
> >
> > If return_consumer_find() returns NULL, uc->ret_handler(..., NULL) can 
> > handle
> > this case itself?
>
> I tried to explain that in the comment above.. we do not want to
> execute session ret_handler at all in this case, because its entry
> counterpart did not run

I understand, but the session ret_handler(..., __u64 *data) can simply do

        // my ->handler() didn't run or it didn't return 0
        if (!data)
                return;

at the start?

Oleg.


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