RE: [for-linus][PATCH 2/5] tracing/uprobe: Fix double perf_event linking on multiprobe uprobe

[David Laight]

From: Peter Zijlstra
> Sent: 21 January 2020 14:50
> On Tue, Jan 21, 2020 at 09:38:49AM -0500, Steven Rostedt wrote:
> > diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> > index 4ee703728aec..03e4e180058d 100644
> > --- a/kernel/trace/trace_probe.h
> > +++ b/kernel/trace/trace_probe.h
> > @@ -230,6 +230,7 @@ struct trace_probe_event {
> >  	struct trace_event_call		call;
> >  	struct list_head 		files;
> >  	struct list_head		probes;
> > +	char				data[0];
> >  };
> 
> Note that this relies on pure 'luck'. If you stick anything <4 bytes in
> between the list_head and the data member it'll come unstuck real fast.

Can you fix it by adding an unnamed struct as in:

struct trace_probe_event {
    	struct {
		struct trace_event_call		call;
		struct list_head 		files;
		struct list_head		probes;
	};
	char				data[0];
};

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)