This is a note to let you know that I've just added the patch titled
drm/bridge: properly refcount DT nodes in aux bridge drivers
to the 6.6-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-bridge-properly-refcount-dt-nodes-in-aux-bridge-.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 09b2aa52ca01bb74251a0afe1bac930edb534b0a
Author: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Date: Sun Dec 17 01:59:10 2023 +0200
drm/bridge: properly refcount DT nodes in aux bridge drivers
[ Upstream commit 6914968a0b52507bf19d85e5fb9e35272e17cd35 ]
The aux-bridge and aux-hpd-bridge drivers didn't call of_node_get() on
the device nodes further used for dev->of_node and platform data. When
bridge devices are released, the reference counts are decreased,
resulting in refcount underflow / use-after-free warnings. Get
corresponding refcounts during AUX bridge allocation.
Reported-by: Luca Weiss <luca.weiss@xxxxxxxxxxxxx>
Fixes: 2a04739139b2 ("drm/bridge: add transparent bridge helper")
Fixes: 26f4bac3d884 ("drm/bridge: aux-hpd: Replace of_device.h with explicit include")
Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20231216235910.911958-1-dmitry.baryshkov@xxxxxxxxxx
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/bridge/aux-bridge.c b/drivers/gpu/drm/bridge/aux-bridge.c
index 49d7c2ab1ecc3..b29980f95379e 100644
--- a/drivers/gpu/drm/bridge/aux-bridge.c
+++ b/drivers/gpu/drm/bridge/aux-bridge.c
@@ -6,6 +6,7 @@
*/
#include <linux/auxiliary_bus.h>
#include <linux/module.h>
+#include <linux/of.h>
#include <drm/drm_bridge.h>
#include <drm/bridge/aux-bridge.h>
@@ -57,7 +58,7 @@ int drm_aux_bridge_register(struct device *parent)
adev->id = ret;
adev->name = "aux_bridge";
adev->dev.parent = parent;
- adev->dev.of_node = parent->of_node;
+ adev->dev.of_node = of_node_get(parent->of_node);
adev->dev.release = drm_aux_bridge_release;
ret = auxiliary_device_init(adev);
diff --git a/drivers/gpu/drm/bridge/aux-hpd-bridge.c b/drivers/gpu/drm/bridge/aux-hpd-bridge.c
index 44bb771211b82..a24b6613cc02d 100644
--- a/drivers/gpu/drm/bridge/aux-hpd-bridge.c
+++ b/drivers/gpu/drm/bridge/aux-hpd-bridge.c
@@ -63,9 +63,9 @@ struct auxiliary_device *devm_drm_dp_hpd_bridge_alloc(struct device *parent, str
adev->id = ret;
adev->name = "dp_hpd_bridge";
adev->dev.parent = parent;
- adev->dev.of_node = parent->of_node;
+ adev->dev.of_node = of_node_get(parent->of_node);
adev->dev.release = drm_aux_hpd_bridge_release;
- adev->dev.platform_data = np;
+ adev->dev.platform_data = of_node_get(np);
ret = auxiliary_device_init(adev);
if (ret) {
