Messages in this thread | | | Date | Tue, 26 May 2015 14:16:19 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2 01/11] perf,x86: Fix event/group validation |
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On Tue, May 26, 2015 at 04:46:07AM -0700, Stephane Eranian wrote: > On Tue, May 26, 2015 at 3:12 AM, Peter Zijlstra <peterz@infradead.org> wrote: > > On Tue, May 26, 2015 at 02:24:38AM -0700, Stephane Eranian wrote: > >> On Fri, May 22, 2015 at 6:40 AM, Peter Zijlstra <peterz@infradead.org> wrote: > >> > On Fri, May 22, 2015 at 03:29:06PM +0200, Peter Zijlstra wrote: > >> >> @@ -788,9 +788,9 @@ int x86_schedule_events(struct cpu_hw_ev > >> >> x86_pmu.start_scheduling(cpuc); > >> >> > >> >> for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) { > >> >> + cpuc->event_constraint[i] = NULL; > >> >
> But where is the code that says: skip reinstalling the constraint > in intel_get_event_constraints() because there is already a (stale) > one? I don't see where that is.
IIRC the problem was that the copy from c2 into c1:
if (c1 && (c1->flags & PERF_X86_EVENT_DYNAMIC)) { bitmap_copy(c1->idxmsk, c2->idxmsk, X86_PMC_IDX_MAX); c1->weight = c2->weight; c2 = c1; }
is incomplete. For instance, flags is not copied, and some code down the line might check that and get wrong flags.
I'm not entirely sure I saw misbehaviour, but I figured I'd better close that hole and rule out this is contributing to fail.
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