Re: [Intel-gfx] [PATCH] drm/i915/pmu: Keep a reference to module while active

On 30/04/2020 19:33, Chris Wilson wrote:

While a perf event is open, keep a reference to the module so we don't remove the driver internals mid-sampling.

Testcase: igt/perf_pmu/module-unload Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: stable@vger.kernel.org

---

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 83c6a8ccd2cb..e991a707bdb7 100644 --- a/drivers/gpu/drm/i915/i915_pmu.c +++ b/drivers/gpu/drm/i915/i915_pmu.c @@ -442,6 +442,7 @@ static u64 count_interrupts(struct drm_i915_private *i915) static void i915_pmu_event_destroy(struct perf_event *event) { WARN_ON(event->parent);

• module_put(THIS_MODULE); }

static int @@ -533,8 +534,10 @@ static int i915_pmu_event_init(struct perf_event *event) if (ret) return ret;

• if (!event->parent)

• if (!event->parent) {

• __module_get(THIS_MODULE);
  

  event->destroy = i915_pmu_event_destroy;
• }

return 0; }

Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com

Regards,

Tvrtko