From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Thu, 30 Apr 2020 18:33:24 +0000 (+0100)
Subject: drm/i915/pmu: Keep a reference to module while active
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=3b55cdeb8f1b71444da866fd2568b1a18ba7f9c3;p=linux.git

drm/i915/pmu: Keep a reference to module while active

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
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200430183324.23984-1-chris@chris-wilson.co.uk
---

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 83c6a8ccd2cb2..e991a707bdb75 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;
 }