Re: [PATCHv4 02/14] uprobe: Add support for session consumer

[Jiri Olsa]

On Mon, Sep 23, 2024 at 12:05:53PM +0200, Oleg Nesterov wrote:
> On 09/23, Jiri Olsa wrote:
> >
> > change below should do what you proposed originally
> 
> LGTM, just one nit below.
> 
> But I guess you need to do this on top of bpf/bpf.git, Andrii has already
> applied your series.

that seems confusing but looks like just that one fix with the
commit link in [1] was applied

[1] https://lore.kernel.org/bpf/172708047825.3261420.5126267811201364070.git-patchwork-notify@xxxxxxxxxx/T/#mb065649b5ab8f7ea5b03c215bdc6555a0b76c0d7

> 
> And to remind, 02/14 must be fixed in any case unless I am totally confused,
> handler_chain() can leak return_instance.

yep it was missing kfree, but it's not needed in this new version

> 
> > also on top of that.. I discussed with Andrii the possibility of dropping
> > the UPROBE_HANDLER_IWANTMYCOOKIE completely and setup cookie for any consumer
> > that has both 'handler' and 'ret_handler' defined, wdyt?
> 
> Up to you. As I said from the very beginning I won't insist on _IWANTMYCOOKIE.

ok

> 
> >  	list_for_each_entry_srcu(uc, &uprobe->consumers, cons_node,
> >  				 srcu_read_lock_held(&uprobes_srcu)) {
> > +		ric = return_consumer_find(ri, &ric_idx, uc->id);
> >  		if (uc->ret_handler)
> > -			uc->ret_handler(uc, ri->func, regs);
> > +			uc->ret_handler(uc, ri->func, regs, ric ? &ric->cookie : NULL);
> >  	}
> >  	srcu_read_unlock(&uprobes_srcu, srcu_idx);
> 
> return_consumer_find() makes no sense if !uc->ret_handler, can you move
> 
> 		ric = return_consumer_find(ri, &ric_idx, uc->id);
> 
> into the "if (uc->ret_handler)" block?

ok, will move that

thanks,
jirka