Re: [PATCH v2 2/4] selftests/ftrace: Add a test to probe module functions

[Masami Hiramatsu <mhiramat@kernel.org>]

On Mon, 3 Jul 2017 12:27:33 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> On Thu, 29 Jun 2017 19:05:37 +0530
> "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> 
> > Add a kprobes test to ensure that we are able to add a probe on a
> > module function using 'p <mod>:<func>' format, without having to
> > specify a probe name.
> > 
> > Suggested-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> > ---
> >  .../testing/selftests/ftrace/test.d/kprobe/probe_module.tc | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >  create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/probe_module.tc
> > 
> > diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/probe_module.tc b/tools/testing/selftests/ftrace/test.d/kprobe/probe_module.tc
> > new file mode 100644
> > index 000000000000..ea7657041ba6
> > --- /dev/null
> > +++ b/tools/testing/selftests/ftrace/test.d/kprobe/probe_module.tc
> > @@ -0,0 +1,14 @@
> > +#!/bin/sh
> > +# description: Kprobe dynamic event - probing module
> > +
> > +[ -f kprobe_events ] || exit_unsupported # this is configurable
> > +
> > +echo 0 > events/enable
> > +echo > kprobe_events
> > +export MOD=`lsmod | head -n 2 | tail -n 1 | cut -f1 -d" "`
> > +export FUNC=`grep -m 1 ".* t .*\\[$MOD\\]" /proc/kallsyms | xargs | cut -f3 -d" "`
> > +[ "x" != "x$MOD" -a "y" != "y$FUNC" ] || exit_untested
> 
> Could you also add below case?
> 
> echo p:probe_$MOD/$FUNC $MOD/$FUNC > kprobe_events 

Oops, it should be something like

echo "p:test_${MOD}_${FUNC} $MOD/$FUNC" > kprobe_events

since we would like to avoid adding new group name for it.

(Adding new group name should be a separated one.)

Thank you,

> 
> This is for "new event with name on module" case, your one is for "new event without name on module (automatic name generation)"
> 
> We should have different test case, because those kicks slightly different parts in kprobe tracer.
> 
> Thank you,
> 
> > +echo p $MOD:$FUNC > kprobe_events
> > +grep $MOD kprobe_events
> > +echo > kprobe_events
> > +clear_trace
> > -- 
> > 2.13.1
> > 
> 
> 
> -- 
> Masami Hiramatsu <mhiramat@kernel.org>


-- 
Masami Hiramatsu <mhiramat@kernel.org>