Elsewhere we manipulate uncore.unclaimed_mmio_check and
i915_param.mmio_debug under the irq lock (e.g. preserving the current
value across a user forcewake grab), but do not protect the manipulation
inside intel_uncore_arm_unclaimed_mmio_detection() from concurrent
access, even from itself. This is an issue as we do call
arm_unclaimed_mmio_detection from multiple threads without coordination.
Suggested-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_uncore.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 05f0cda18501..3ad302c66254 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -2283,8 +2283,12 @@ bool intel_uncore_unclaimed_mmio(struct drm_i915_private *dev_priv)
bool
intel_uncore_arm_unclaimed_mmio_detection(struct drm_i915_private *dev_priv)
{
+ bool ret = false;
+
+ spin_lock_irq(&dev_priv->uncore.lock);
+
if (unlikely(dev_priv->uncore.unclaimed_mmio_check <= 0))
- return false;
+ goto out;
if (unlikely(intel_uncore_unclaimed_mmio(dev_priv))) {
if (!i915_modparams.mmio_debug) {
@@ -2294,10 +2298,13 @@ intel_uncore_arm_unclaimed_mmio_detection(struct drm_i915_private *dev_priv)
i915_modparams.mmio_debug++;
}
dev_priv->uncore.unclaimed_mmio_check--;
- return true;
+ ret = true;
}
- return false;
+out:
+ spin_unlock_irq(&dev_priv->uncore.lock);
+
+ return ret;
}
static enum forcewake_domains
--
2.19.0.rc1
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