arch/powerpc/perf/core-book3s.c checks sample_type, see
if (event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK) {
...
perf_sample_save_brstack(&data, event, &cpuhw->bhrb_stack, NULL);
}
So I think we don't need the "fixes:" line.
On Fri, May 10, 2024 at 2:30 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> On Fri, May 10, 2024 at 12:14 PM Yabin Cui <yabinc@xxxxxxxxxx> wrote:
> >
> > Check sample_type in perf_sample_save_brstack() to prevent
> > saving branch stack data when it isn't required.
> >
> > Suggested-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > Signed-off-by: Yabin Cui <yabinc@xxxxxxxxxx>
>
> It seems powerpc has the similar bug, then you need this:
>
> Fixes: eb55b455ef9c ("perf/core: Add perf_sample_save_brstack() helper")
>
> Thanks,
> Namhyung
>
> > ---
> > arch/x86/events/amd/core.c | 3 +--
> > arch/x86/events/core.c | 3 +--
> > arch/x86/events/intel/ds.c | 3 +--
> > include/linux/perf_event.h | 13 ++++++++-----
> > 4 files changed, 11 insertions(+), 11 deletions(-)
> >
> > diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
> > index 985ef3b47919..fb9bf3aa1b42 100644
> > --- a/arch/x86/events/amd/core.c
> > +++ b/arch/x86/events/amd/core.c
> > @@ -967,8 +967,7 @@ static int amd_pmu_v2_handle_irq(struct pt_regs *regs)
> > if (!x86_perf_event_set_period(event))
> > continue;
> >
> > - if (has_branch_stack(event))
> > - perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
> > + perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
> >
> > if (perf_event_overflow(event, &data, regs))
> > x86_pmu_stop(event, 0);
> > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
> > index 5b0dd07b1ef1..ff5577315938 100644
> > --- a/arch/x86/events/core.c
> > +++ b/arch/x86/events/core.c
> > @@ -1702,8 +1702,7 @@ int x86_pmu_handle_irq(struct pt_regs *regs)
> >
> > perf_sample_data_init(&data, 0, event->hw.last_period);
> >
> > - if (has_branch_stack(event))
> > - perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
> > + perf_sample_save_brstack(&data, event, &cpuc->lbr_stack, NULL);
> >
> > if (perf_event_overflow(event, &data, regs))
> > x86_pmu_stop(event, 0);
> > diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> > index c2b5585aa6d1..f25236ffa28f 100644
> > --- a/arch/x86/events/intel/ds.c
> > +++ b/arch/x86/events/intel/ds.c
> > @@ -1754,8 +1754,7 @@ static void setup_pebs_fixed_sample_data(struct perf_event *event,
> > if (x86_pmu.intel_cap.pebs_format >= 3)
> > setup_pebs_time(event, data, pebs->tsc);
> >
> > - if (has_branch_stack(event))
> > - perf_sample_save_brstack(data, event, &cpuc->lbr_stack, NULL);
> > + perf_sample_save_brstack(data, event, &cpuc->lbr_stack, NULL);
> > }
> >
> > static void adaptive_pebs_save_regs(struct pt_regs *regs,
> > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> > index 8617815456b0..ecfbe22ff299 100644
> > --- a/include/linux/perf_event.h
> > +++ b/include/linux/perf_event.h
> > @@ -1269,6 +1269,11 @@ static inline void perf_sample_save_raw_data(struct perf_sample_data *data,
> > data->sample_flags |= PERF_SAMPLE_RAW;
> > }
> >
> > +static inline bool has_branch_stack(struct perf_event *event)
> > +{
> > + return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK;
> > +}
> > +
> > static inline void perf_sample_save_brstack(struct perf_sample_data *data,
> > struct perf_event *event,
> > struct perf_branch_stack *brs,
> > @@ -1276,6 +1281,9 @@ static inline void perf_sample_save_brstack(struct perf_sample_data *data,
> > {
> > int size = sizeof(u64); /* nr */
> >
> > + if (!has_branch_stack(event))
> > + return;
> > +
> > if (branch_sample_hw_index(event))
> > size += sizeof(u64);
> > size += brs->nr * sizeof(struct perf_branch_entry);
> > @@ -1665,11 +1673,6 @@ extern void perf_bp_event(struct perf_event *event, void *data);
> > # define perf_arch_bpf_user_pt_regs(regs) regs
> > #endif
> >
> > -static inline bool has_branch_stack(struct perf_event *event)
> > -{
> > - return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK;
> > -}
> > -
> > static inline bool needs_branch_stack(struct perf_event *event)
> > {
> > return event->attr.branch_sample_type != 0;
> > --
> > 2.45.0.118.g7fe29c98d7-goog
> >
