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
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>
