Re: [PATCH v5 3/5] tracing/probes: Fix to update dynamic data counter if fetcharg uses it
From: Google
Date: Thu Jul 13 2023 - 10:34:26 EST
On Thu, 13 Jul 2023 09:34:36 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Tue, 11 Jul 2023 23:15:48 +0900
> "Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx> wrote:
>
> > From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> >
> > Fix to update dynamic data counter ('dyndata') and max length ('maxlen')
> > only if the fetcharg uses the dynamic data. Also get out arg->dynamic
> > from unlikely(). This makes dynamic data address wrong if
> > process_fetch_insn() returns error on !arg->dynamic case.
> >
> > Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> > Link: https://lore.kernel.org/all/20230710233400.5aaf024e@xxxxxxxxxxxxxxxxxx/
> > Fixes: 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
>
> Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Thank you! I'll pull this series.
>
> -- Steve
>
> > ---
> > kernel/trace/trace_probe_tmpl.h | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h
> > index ed9d57c6b041..185da001f4c3 100644
> > --- a/kernel/trace/trace_probe_tmpl.h
> > +++ b/kernel/trace/trace_probe_tmpl.h
> > @@ -267,11 +267,13 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec,
> > if (unlikely(arg->dynamic))
> > *dl = make_data_loc(maxlen, dyndata - base);
> > ret = process_fetch_insn(arg->code, rec, dl, base);
> > - if (unlikely(ret < 0 && arg->dynamic)) {
> > - *dl = make_data_loc(0, dyndata - base);
> > - } else {
> > - dyndata += ret;
> > - maxlen -= ret;
> > + if (arg->dynamic) {
> > + if (unlikely(ret < 0)) {
> > + *dl = make_data_loc(0, dyndata - base);
> > + } else {
> > + dyndata += ret;
> > + maxlen -= ret;
> > + }
> > }
> > }
> > }
>
--
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>