Messages in this thread | | | Date | Tue, 18 Apr 2023 12:25:45 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf/core: Fix perf_sample_data not properly initialized for different swevents in perf_tp_event() |
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On Tue, Apr 18, 2023 at 09:35:23AM +0800, Yang Jihong wrote:
> > I'm thinking perhaps those flags that update ->dyn_size are the problem? > > At the same time, Should you not also then clear dyn_size?
> Yes, according to the code, dyn_size should also be cleared. > Maybe we need to change it to the following, which would be more > appropriate? > > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -10144,14 +10144,14 @@ void perf_tp_event(u16 event_type, u64 count, void > *record, int entry_size, > }, > }; > > - perf_sample_data_init(&data, 0, 0); > - perf_sample_save_raw_data(&data, &raw); > - > perf_trace_buf_update(record, event_type); > > hlist_for_each_entry_rcu(event, head, hlist_entry) { > - if (perf_tp_event_match(event, &data, regs)) > + if (perf_tp_event_match(event, &data, regs)) { > + perf_sample_data_init(&data, 0, 0); > + perf_sample_save_raw_data(&data, &raw); > perf_swevent_event(event, count, &data, regs); > + } > }
That is certainly the safe option. I just went through the list and while there's certainly a number of options we'll recompute for naught, most of them are indeed either dyn_size or event specific :/
So yeah, please send the above as v2.
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