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    SubjectRE: [PATCH] perf/x86: Fix overlap counter scheduling bug
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    > >
    > >
    > > diff --git a/arch/x86/events/intel/uncore_snbep.c
    > > b/arch/x86/events/intel/uncore_snbep.c
    > > index 272427700d48..71bc348736bd 100644
    > > --- a/arch/x86/events/intel/uncore_snbep.c
    > > +++ b/arch/x86/events/intel/uncore_snbep.c
    > > @@ -669,7 +669,7 @@ static struct event_constraint
    > snbep_uncore_cbox_constraints[] = {
    > > UNCORE_EVENT_CONSTRAINT(0x1c, 0xc),
    > > UNCORE_EVENT_CONSTRAINT(0x1d, 0xc),
    > > UNCORE_EVENT_CONSTRAINT(0x1e, 0xc),
    > > - EVENT_CONSTRAINT_OVERLAP(0x1f, 0xe, 0xff),
    > > + UNCORE_EVENT_CONSTRAINT(0x1f, 0xc); /* should be 0x0e but that
    > gives
    > > +scheduling pain */

    I think the crash is caused by the overlap bit.
    Why not just revert the previous patch?

    If overlap bit is removed, the perf_sched_save_state will never be touched.
    Why we have to reduce a counter?

    Thanks,
    Kan

    > > UNCORE_EVENT_CONSTRAINT(0x21, 0x3),
    > > UNCORE_EVENT_CONSTRAINT(0x23, 0x3),
    > > UNCORE_EVENT_CONSTRAINT(0x31, 0x3),
    > >

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