Re: [PATCH] tracing/probe: reverse arguments to list_add

[Masami Hiramatsu]

On Thu, 7 May 2020 16:50:53 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> On Thu,  7 May 2020 21:30:08 +0200
> Julia Lawall <Julia.Lawall@xxxxxxxx> wrote:
> 
> > Elsewhere in the file, the function trace_kprobe_has_same_kprobe uses
> > a trace_probe_event.probes object as the second argument of
> > list_for_each_entry, ie as a list head, while the list_for_each_entry
> > iterates over the list fields of the trace_probe structures, making
> > them the list elements.  So, exchange the arguments on the list_add
> > call to put the list head in the second argument.
> > 
> > Since both list_head structures were just initialized, this problem
> > did not cause any loss of information.
> > 

Oops, good catch!

> > Fixes: 60d53e2c3b75 ("tracing/probe: Split trace_event related data from trace_probe")
> > Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxxx>
> 
> Masami,
> 
> Can you give a Reviewed-by to this?

Yes, thanks Julia!

Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Thank you,
> 
> -- Steve
> 
> > 
> > ---
> >  kernel/trace/trace_probe.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> > index ab8b6436d53f..b8a928e925c7 100644
> > --- a/kernel/trace/trace_probe.c
> > +++ b/kernel/trace/trace_probe.c
> > @@ -1006,7 +1006,7 @@ int trace_probe_init(struct trace_probe *tp, const char *event,
> >  	INIT_LIST_HEAD(&tp->event->class.fields);
> >  	INIT_LIST_HEAD(&tp->event->probes);
> >  	INIT_LIST_HEAD(&tp->list);
> > -	list_add(&tp->event->probes, &tp->list);
> > +	list_add(&tp->list, &tp->event->probes);
> >  
> >  	call = trace_probe_event_call(tp);
> >  	call->class = &tp->event->class;
> 


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>