Re: [PATCH v4 1/3] tracing: Add support for recording tgid of tasks

[Steven Rostedt <rostedt@goodmis.org>]

On Mon, 26 Jun 2017 12:10:04 -0700
Joel Fernandes <joelaf@google.com> wrote:


> > That seems Ok with me to do, I think a valid point.
> >
> > I think that I should do it in the second call to
> > tracing_start_tgid_record too then (__ftrace_event_enable_disable) to
> > error out if the allocation fails.
> >
> > While going this code I again, I noticed another potential issue in
> > __ftrace_event_enable_disable  
> 
> Sorry I hit send too soon!
> 
> I was saying, While going through this code again I noticed another
> potential issue in __ftrace_event_enable_disable in existing code:
> 
> Here we do:
> ret = call->class->reg(call, TRACE_REG_REGISTER, file);
> 
> But in the error handling path we only do a
> tracing_stop_cmdline_record() and not clear the
> EVENT_FILE_FL_RECORDED_CMD_BIT flag. Is that not an issue? I am
> guessing because enabling of the event itself will fail, that's Ok.
> But just to keep it consistent, I am thinking if we should just clear
> the bit here.

Yeah, we should probably add some better error handling for failed
setting of events. But the tgid-map is low hanging fruit to get
right ;-)

-- Steve