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Patch "drm: Release driver tracking before making the object available again" has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Aug 27, 2017

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This is a note to let you know that I've just added the patch titled

drm: Release driver tracking before making the object available again

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-release-driver-tracking-before-making-the-object-available-again.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From fe4600a548f2763dec91b3b27a1245c370ceee2a Mon Sep 17 00:00:00 2001

From: Chris Wilson <[email protected]>
Date: Sat, 19 Aug 2017 13:05:58 +0100
Subject: drm: Release driver tracking before making the object available again
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From: Chris Wilson <[email protected]>

commit fe4600a548f2763dec91b3b27a1245c370ceee2a upstream.

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)")

---
 drivers/gpu/drm/drm_gem.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
drivers/gpu/drm/drm_gem.c +3 -3
@@ -255,13 +255,13 @@ drm_gem_object_release_handle(int id, vo
 	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);
-
 	drm_gem_object_handle_unreference_unlocked(obj);
 
 	return 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drm-release-driver-tracking-before-making-the-object-available-again.patch