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

David Laight
2020-01-21T14:59:41Z

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

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