Patch "drm: Release reference from blob lookup after replacing property" has been added to the 4.8-stable tree

Patch "drm: Release reference from blob lookup after replacing property" has been added to the 4.8-stable tree

[gregkh]

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

    drm: Release reference from blob lookup after replacing property

to the 4.8-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-reference-from-blob-lookup-after-replacing-property.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From cac5fcedaabdadf150c8a9be9fee76defc8ba444 Mon Sep 17 00:00:00 2001
From: Felix Monninger <felix.monninger@gmail.com>
Date: Tue, 25 Oct 2016 22:28:08 +0100
Subject: drm: Release reference from blob lookup after replacing property
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Felix Monninger <felix.monninger@gmail.com>

commit cac5fcedaabdadf150c8a9be9fee76defc8ba444 upstream.

drm_property_lookup_blob() returns a reference to the returned blob, and
drm_atomic_replace_property_blob() takes a references to the blob it
stores, so afterwards we are left owning a reference to the new_blob that
we never release, and thus leak memory every time we update a property
such as during drm_atomic_helper_legacy_gamma_set().

v2: update credentials, drm_property_unreference_blob() is NULL safe and
NULL is passed consistently to it throughout drm_atomic.c so do so here.

Reported-by: Felix Monninger <felix.monninger@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98420
Signed-off-by: Felix Monninger <felix.monninger@gmail.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Fixes: 5488dc16fde7 ("drm: introduce pipe color correction properties")
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161025212808.3908-1-chris@chris-wilson.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/drm_atomic.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -420,18 +420,21 @@ drm_atomic_replace_property_blob_from_id
 					 ssize_t expected_size,
 					 bool *replaced)
 {
-	struct drm_device *dev = crtc->dev;
 	struct drm_property_blob *new_blob = NULL;
 
 	if (blob_id != 0) {
-		new_blob = drm_property_lookup_blob(dev, blob_id);
+		new_blob = drm_property_lookup_blob(crtc->dev, blob_id);
 		if (new_blob == NULL)
 			return -EINVAL;
-		if (expected_size > 0 && expected_size != new_blob->length)
+
+		if (expected_size > 0 && expected_size != new_blob->length) {
+			drm_property_unreference_blob(new_blob);
 			return -EINVAL;
+		}
 	}
 
 	drm_atomic_replace_property_blob(blob, new_blob, replaced);
+	drm_property_unreference_blob(new_blob);
 
 	return 0;
 }


Patches currently in stable-queue which might be from felix.monninger@gmail.com are

queue-4.8/drm-release-reference-from-blob-lookup-after-replacing-property.patch