Commit 6914968a authored by Dmitry Baryshkov's avatar Dmitry Baryshkov
Browse files

drm/bridge: properly refcount DT nodes in aux bridge drivers 



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: default avatarLuca Weiss <luca.weiss@fairphone.com>
Fixes: 2a047391 ("drm/bridge: add transparent bridge helper")
Fixes: 26f4bac3 ("drm/bridge: aux-hpd: Replace of_device.h with explicit include")
Reviewed-by: default avatarNeil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231216235910.911958-1-dmitry.baryshkov@linaro.org


Signed-off-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
parent 8a53e29f

drivers/gpu/drm/bridge/aux-bridge.c

+2 −1
Original line number Diff line number Diff line
@@ -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);

drivers/gpu/drm/bridge/aux-hpd-bridge.c

+2 −2
Original line number Diff line number Diff line
@@ -68,9 +68,9 @@ struct device *drm_dp_hpd_bridge_register(struct device *parent, 
	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) {