[PATCH] drm/meson: Avoid use-after-free issues with crtc

[Zhang Kunbo]

It's dangerous to call drm_crtc_init_with_planes() whose second
argument is allocated with devm_kzalloc() [1][2].

Use drmm_kzalloc instead to avoid UAF.

[1] https://lore.kernel.org/all/a830685d8b10a00cfe0a86db1ee9fb13@ispras.ru
[2] https://lore.kernel.org/all/2111196.TG1k3f53YQ@avalon

Fixes: bbbe775ec5b5 ("drm: Add support for Amlogic Meson Graphic Controller")
Signed-off-by: Zhang Kunbo <zhangkunbo at huawei.com>
---
 drivers/gpu/drm/meson/meson_crtc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_crtc.c b/drivers/gpu/drm/meson/meson_crtc.c
index d70616da8ce2..603022554a48 100644
--- a/drivers/gpu/drm/meson/meson_crtc.c
+++ b/drivers/gpu/drm/meson/meson_crtc.c
@@ -17,6 +17,7 @@
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_vblank.h>
+#include <drm/drm_managed.h>
 
 #include "meson_crtc.h"
 #include "meson_plane.h"
@@ -72,7 +73,6 @@ static void meson_crtc_disable_vblank(struct drm_crtc *crtc)
 static const struct drm_crtc_funcs meson_crtc_funcs = {
 	.atomic_destroy_state	= drm_atomic_helper_crtc_destroy_state,
 	.atomic_duplicate_state = drm_atomic_helper_crtc_duplicate_state,
-	.destroy		= drm_crtc_cleanup,
 	.page_flip		= drm_atomic_helper_page_flip,
 	.reset			= drm_atomic_helper_crtc_reset,
 	.set_config             = drm_atomic_helper_set_config,
@@ -677,14 +677,14 @@ int meson_crtc_create(struct meson_drm *priv)
 	struct drm_crtc *crtc;
 	int ret;
 
-	meson_crtc = devm_kzalloc(priv->drm->dev, sizeof(*meson_crtc),
+	meson_crtc = drmm_kzalloc(priv->drm, sizeof(*meson_crtc),
 				  GFP_KERNEL);
 	if (!meson_crtc)
 		return -ENOMEM;
 
 	meson_crtc->priv = priv;
 	crtc = &meson_crtc->base;
-	ret = drm_crtc_init_with_planes(priv->drm, crtc,
+	ret = drmm_crtc_init_with_planes(priv->drm, crtc,
 					priv->primary_plane, NULL,
 					&meson_crtc_funcs, "meson_crtc");
 	if (ret) {
-- 
2.34.1