drm/rockchip: dw_dp: Switch to drmm_kzalloc()

Driver makes use of drmm_encoder_init() to initialize the encoder and
automatically handle the cleanup by registering drm_encoder_cleanup()
with drmm_add_action().

However, the internal structure containing the encoder part gets
allocated with devm_kzalloc(), which happens while component_bind_all()
is being called from Rockchip DRM driver.  The component framework
further ensures it is deallocated as part of releasing all the resources
claimed during bind, which is triggered from component_unbind_all().

When the reference to the DRM device gets eventually dropped via
drm_dev_put() in rockchip_drm_unbind(), drmm_encoder_alloc_release()
attempts to access the now released encoder structure, leading to
use-after-free.

Ensure driver's internal structure is still reachable on encoder cleanup
by switching from a device-managed allocation to a drm-managed one.

Fixes: d68ba7bac955 ("drm/rockchip: Add RK3588 DPTX output support")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patch.msgid.link/20260310-drm-rk-fixes-v2-2-645ecfb43f49@collabora.com

diff --git a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
index dac3d202971edaecfd0db0688047b7a5b6f2d4ee..532af476d250a514f7de26531146d923e801d54d 100644 (file)
--- a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
@@ -13,6 +13,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_bridge_connector.h>
+#include <drm/drm_managed.h>
 #include <drm/drm_of.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
@@ -82,7 +83,7 @@ static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *
        struct drm_connector *connector;
        int ret;
 
-       dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
+       dp = drmm_kzalloc(drm_dev, sizeof(*dp), GFP_KERNEL);
        if (!dp)
                return -ENOMEM;