On 17-07-18 15:36:11, Tvrtko Ursulin wrote:
From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Without this I can get a null ptr deref when trying to access
our events with perf.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
This definitely seems unsafe, but should be squashed in somewhere earlier...
---
drivers/gpu/drm/i915/i915_pmu.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 4d61a1e72ee6..4195d89b1c82 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -183,8 +183,11 @@ static int engine_event_init(struct perf_event *event)
return 0;
}
+static DEFINE_PER_CPU(struct pt_regs, i915_pmu_pt_regs);
+
static enum hrtimer_restart hrtimer_sample(struct hrtimer *hrtimer)
{
+ struct pt_regs *regs = this_cpu_ptr(&i915_pmu_pt_regs);
struct perf_sample_data data;
struct perf_event *event;
u64 period;
@@ -196,7 +199,7 @@ static enum hrtimer_restart hrtimer_sample(struct hrtimer *hrtimer)
event->pmu->read(event);
perf_sample_data_init(&data, 0, event->hw.last_period);
- perf_event_overflow(event, &data, NULL);
+ perf_event_overflow(event, &data, regs);
period = max_t(u64, 10000, event->hw.sample_period);
hrtimer_forward_now(hrtimer, ns_to_ktime(period));
--
2.9.4
--
Ben Widawsky, Intel Open Source Technology Center
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