Messages in this thread | | | Date | Mon, 24 Oct 2016 14:26:39 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCHv2] perf powerpc: Don't call perf_event_disable from atomic context |
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On Thu, Oct 06, 2016 at 02:33:01PM +0200, Jiri Olsa wrote: > diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c > index aec9a1b1d25b..4d3bcbbf626a 100644 > --- a/arch/powerpc/kernel/hw_breakpoint.c > +++ b/arch/powerpc/kernel/hw_breakpoint.c > @@ -275,7 +275,7 @@ int __kprobes hw_breakpoint_handler(struct die_args *args) > if (!stepped) { > WARN(1, "Unable to handle hardware breakpoint. Breakpoint at " > "0x%lx will be disabled.", info->address); > - perf_event_disable(bp); > + perf_event_disable_inatomic(bp); > goto out; > } > /* > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h > index 5c5362584aba..c794fd84a595 100644 > --- a/include/linux/perf_event.h > +++ b/include/linux/perf_event.h > @@ -1248,6 +1248,7 @@ extern u64 perf_swevent_set_period(struct perf_event *event); > extern void perf_event_enable(struct perf_event *event); > extern void perf_event_disable(struct perf_event *event); > extern void perf_event_disable_local(struct perf_event *event); > +extern void perf_event_disable_inatomic(struct perf_event *event); > extern void perf_event_task_tick(void); > #else /* !CONFIG_PERF_EVENTS: */ > static inline void * > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 7c0d263f6bc5..3d650ccf4def 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -1960,6 +1960,13 @@ void perf_event_disable(struct perf_event *event) > } > EXPORT_SYMBOL_GPL(perf_event_disable); > > +void perf_event_disable_inatomic(struct perf_event *event) > +{ > + event->pending_kill = POLL_HUP; > + event->pending_disable = 1; > + irq_work_queue(&event->pending); > +} > + > static void perf_set_shadow_time(struct perf_event *event, > struct perf_event_context *ctx, > u64 tstamp) > @@ -7074,9 +7081,7 @@ static int __perf_event_overflow(struct perf_event *event, > event->pending_kill = POLL_IN; > if (events && atomic_dec_and_test(&event->event_limit)) { > ret = 1; > - event->pending_kill = POLL_HUP; > - event->pending_disable = 1; > - irq_work_queue(&event->pending); > + perf_event_disable_inatomic(event); > } > > event->overflow_handler(event, data, regs);
I'm a wee bit confused on the event->pending_kill assignment in that helper. AFAICT that's not actually used in the PPC case, and if for some reason, pending_wakeup gets set, do we want to deliver a HUP? The old code didn't do that.
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