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Subject[PATCH] i915-pmu: Add extra check engine
Date
Return value of a function 'intel_engine_lookup_user' is dereferenced at i915_pmu.c:708
without checking for null, but it is usually checked for this function

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Denis Arefev <arefev@swemel.ru>
---
drivers/gpu/drm/i915/i915_pmu.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index 69c0fa20eba1..33db49ffac3d 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -704,8 +704,10 @@ static void i915_pmu_disable(struct perf_event *event)
* Decrement the reference count and clear the enabled
* bitmask when the last listener on an event goes away.
*/
- if (--engine->pmu.enable_count[sample] == 0)
- engine->pmu.enable &= ~BIT(sample);
+ if (engine != NULL) {
+ if (--engine->pmu.enable_count[sample] == 0)
+ engine->pmu.enable &= ~BIT(sample);
+ }
}

GEM_BUG_ON(bit >= ARRAY_SIZE(pmu->enable_count));
--
2.25.1
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