On Tue, 7 Nov 2023 09:40:45 +0900
Masami Hiramatsu (Google) <mhira...@kernel.org> wrote:
> On Mon, 6 Nov 2023 17:28:11 -0500
> Steven Rostedt <rost...@goodmis.org> wrote:
>
> > On Sat, 4 Nov 2023 01:05:34 +0900
> > "Masami Hiramatsu (Google)" <mhira...@kernel.org> wrote:
> >
> > > From: Masami Hiramatsu (Google) <mhira...@kernel.org>
> > >
> > > Fix to check the tracepoint event is not valid with $retval.
> > > The commit 08c9306fc2e3 ("tracing/fprobe-event: Assume fprobe is
> > > a return event by $retval") introduced automatic return probe
> > > conversion with $retval. But since tracepoint event does not
> > > support return probe, $retval is not acceptable.
> >
> > Can you add the command that causes this to fail.
>
> Actually this doesn't command fail but it expected to fail.
>
> $ echo "t kfree $retval" >> dynamic_events
Wait, with some configuration, this doesn't cause a problem.
Let me try to reproduce the issue...
Thank you,
>
> This should be rejected because 't' (tracepoint) should not be
> a return probe. Without this fix, this is accepted.
> (But it traces a random return value because the tracepoint function
> will return 'void'.)
>
> Thank you,
>
> >
> > -- Steve
> >
> > >
> > > Fixes: 08c9306fc2e3 ("tracing/fprobe-event: Assume fprobe is a return
> > > event by $retval")
> > > Cc: sta...@vger.kernel.org
> > > Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
> > > ---
> > > kernel/trace/trace_fprobe.c | 9 +++++----
> > > 1 file changed, 5 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
> > > index 8bfe23af9c73..7d2ddbcfa377 100644
> > > --- a/kernel/trace/trace_fprobe.c
> > > +++ b/kernel/trace/trace_fprobe.c
> > > @@ -927,11 +927,12 @@ static int parse_symbol_and_return(int argc, const
> > > char *argv[],
> > > for (i = 2; i < argc; i++) {
> > > tmp = strstr(argv[i], "$retval");
> > > if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
> > > + if (is_tracepoint) {
> > > + trace_probe_log_set_index(i);
> > > + trace_probe_log_err(tmp - argv[i],
> > > RETVAL_ON_PROBE);
> > > + return -EINVAL;
> > > + }
> > > *is_return = true;
> > > - /*
> > > - * NOTE: Don't check is_tracepoint here, because it will
> > > - * be checked when the argument is parsed.
> > > - */
> > > break;
> > > }
> > > }
> >
>
>
> --
> Masami Hiramatsu (Google) <mhira...@kernel.org>
--
Masami Hiramatsu (Google) <mhira...@kernel.org>
