Re: [PATCH 2/4] ftrace/instances: Clear function triggers when removing instances

Naveen N. Rao
2017-06-06T17:38:16Z

On 2017/06/06 11:06AM, Shuah Khan wrote:
> On 05/16/2017 12:33 PM, Steven Rostedt wrote:
> > On Tue, 16 May 2017 23:14:23 +0530
> > "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> >
> >> On 2017/05/16 07:31PM, Naveen N. Rao wrote:
> >>> On 2017/05/15 10:20PM, Steven Rostedt wrote:
> >>>> On Sun, 14 May 2017 01:01:02 +0530
> >>>> "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> >>>>
> >>>
> >>> [snip]
> >>>
> >>>>> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> >>>>> index c4536c449021..3f2aed4ad1ed 100644
> >>>>> --- a/kernel/trace/trace.c
> >>>>> +++ b/kernel/trace/trace.c
> >>>>> @@ -7550,6 +7550,7 @@ static int instance_rmdir(const char *name)
> >>>>> }
> >>>>>
> >>>>> tracing_set_nop(tr);
> >>>>> + clear_ftrace_function_probes(tr);
> >>>>> event_trace_del_tracer(tr);
> >>>>> ftrace_clear_pids(tr);
> >>>>> ftrace_destroy_function_files(tr);
> >>>>> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> >>>>> index 291a1bca5748..98e0845f7235 100644
> >>>>> --- a/kernel/trace/trace.h
> >>>>> +++ b/kernel/trace/trace.h
> >>>>> @@ -980,6 +980,7 @@ register_ftrace_function_probe(char *glob, struct trace_array *tr,
> >>>>> extern int
> >>>>> unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
> >>>>> struct ftrace_probe_ops *ops);
> >>>>> +extern void clear_ftrace_function_probes(struct trace_array *tr);
> >>>>
> >>>> This needs to have a stub function when CONFIG_DYNAMIC_FTRACE is not
> >>>> defined. Otherwise we have:
> >>>>
> >>>> kernel/trace/trace.c:7553:2: error: implicit declaration of function 'clear_ftrace_function_probes' [-Werror=implicit-function-declaration]
> >>>> clear_ftrace_function_probes(tr);
> >>>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >>
> >> The prototype in trace.h is actually guarded by:
> >> #if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
> >>
> >> So, I will guard the call to clear_ftrace_function_probes() in trace.c
> >> with the same.
> >>
> >
> > No, the proper thing to do is to make a stub function in the else part
> > of the #if that the prototype was declared in.
> >
> > static inline void clear_ftrace_function_probes(struct trace_array *tr)
> > {
> > }
> >
> > Please, lets limit the #ifdef ugliness from the code.
> >
> > -- Steve
> >
> >
>
>
> Hi Steve,
>
> Are you good with this patch series. I am looking to see which
> of these should go into 4.13-rc1 - please ack individual patches
> that should be pulled into 4.13-rc1

Hi Shuah,
I see that Steven has already sent v2 of this series to Linus, including
the selftest patches:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1399833.html
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1399832.html

And I also noticed (after I came back from vacation) that Steven had
fixed the #ifdef ugliness I had introduced..

Thanks,
Naveen