From 186507e9e8e89d5920305fdffd8cbba6366da795 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Tue, 23 Apr 2013 23:15:29 -0700 Subject: [PATCH] drm/i915: Assert mutex_is_locked on context lookup Because our context refcounting doesn't grab a ref at lookup time, it is unsafe to do so without the lock. NOTE: We don't have an easy way to put the assertion in the lookup function which is where this really belongs. Context switching is good enough because it actually asserts even more correctness by protecting the default_context. Signed-off-by: Ben Widawsky Reviewed-by: Jesse Barnes [danvet: s/BUG/WARN/] Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem_context.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index efa0ede5c67..c81ae52c8c2 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -463,6 +463,8 @@ int i915_switch_context(struct intel_ring_buffer *ring, if (dev_priv->hw_contexts_disabled) return 0; + WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex)); + if (ring != &dev_priv->ring[RCS]) return 0; -- 2.34.1