Re: [PATCH] tracepoints: prevents null probe from being added

[Steven Rostedt]

On Wed, 2013-03-20 at 14:01 -0400, Mathieu Desnoyers wrote:
> * Steven Rostedt (rostedt@xxxxxxxxxxx) wrote:
> > On Wed, 2013-03-20 at 12:18 +0900, kpark3469@xxxxxxxxx wrote:
> > > From: Sahara <keun-o.park@xxxxxxxxxxxxx>
> > > 
> > > Somehow tracepoint_entry_add/remove_probe functions allow a null probe
> > > function.
> > 
> > You actually hit this in practice, or is this just something that you
> > observe from code review?
> > 
> > >  Especially on getting a null probe in remove function, it seems
> > > to be used to remove all probe functions in the entry.
> > 
> > Hmm, that actually sounds like a feature.
> 
> Yep. It's been a long time since I wrote this code, but the removal code
> seems to use NULL probe pointer to remove all probes for a given
> tracepoint.
> 
> I'd be tempted to just validate non-NULL probe within
> tracepoint_entry_add_probe() and let other sites as is, just in case
> anyone would be using this feature.
> 
> I cannot say that I have personally used this "remove all" feature much
> though.
> 

I agree. I don't see anything wrong in leaving the null probe feature in
the removal code. But updating the add code looks like a proper change.

-- Steve


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