[Intel-gfx] [PATCH] drm/i915/fbc: __intel_fbc_cleanup_cfb() may be called multiple times

[Chris Wilson]

Avoid releasing the same stolen nodes causing a use-after-free and/or
explosions as the self-checks fail, as __intel_fbc_cleanup_cfb() may be
called multiple times during module unload.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_fbc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
index 2a3f1333c8ff..ab676c6756af 100644
--- a/drivers/gpu/drm/i915/display/intel_fbc.c
+++ b/drivers/gpu/drm/i915/display/intel_fbc.c
@@ -537,13 +537,15 @@ static void __intel_fbc_cleanup_cfb(struct drm_i915_private *dev_priv)
 {
 	struct intel_fbc *fbc = &dev_priv->fbc;
 
-	if (drm_mm_node_allocated(&fbc->compressed_fb))
-		i915_gem_stolen_remove_node(dev_priv, &fbc->compressed_fb);
+	if (!drm_mm_node_allocated(&fbc->compressed_fb))
+		return;
 
 	if (fbc->compressed_llb) {
 		i915_gem_stolen_remove_node(dev_priv, fbc->compressed_llb);
 		kfree(fbc->compressed_llb);
 	}
+
+	i915_gem_stolen_remove_node(dev_priv, &fbc->compressed_fb);
 }
 
 void intel_fbc_cleanup_cfb(struct drm_i915_private *dev_priv)
-- 
2.25.0