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 <[email protected]> Signed-off-by: Chris Wilson <[email protected]> Cc: Mika Kuoppala <[email protected]> --- 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 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
