[PATCH 2/3] drm: Release driver tracking before making the object available again

Chris Wilson chris at chris-wilson.co.uk
Sat Aug 19 12:52:27 UTC 2017

This is the same bug as we fixed in commit f6cd7daecff5 ("drm: Release
driver references to handle before making it available again"), but now
the exposure is via the PRIME lookup tables. If we remove the
object/handle from the PRIME lut, then a new request for the same
object/fd will generate a new handle, thus for a short window that
object is known to userspace by two different handles. Fix this by
releasing the driver tracking before PRIME.

Fixes: 0ff926c7d4f0 ("drm/prime: add exported buffers to current fprivs
imported buffer list (v2)")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Rob Clark <robdclark at gmail.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Thierry Reding <treding at nvidia.com>
Cc: stable at vger.kernel.org
 drivers/gpu/drm/drm_gem.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index ad4e9cfe48a2..88c6d78ee2d5 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -255,13 +255,13 @@ drm_gem_object_release_handle(int id, void *ptr, void *data)
 	struct drm_gem_object *obj = ptr;
 	struct drm_device *dev = obj->dev;
+	if (dev->driver->gem_close_object)
+		dev->driver->gem_close_object(obj, file_priv);
 	if (drm_core_check_feature(dev, DRIVER_PRIME))
 		drm_gem_remove_prime_handles(obj, file_priv);
 	drm_vma_node_revoke(&obj->vma_node, file_priv);
-	if (dev->driver->gem_close_object)
-		dev->driver->gem_close_object(obj, file_priv);
 	return 0;

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