[PATCH 2/2] soc: qcom: smem_state: Add refcounting for the 'state->of_node'

[Liang He <windhl@xxxxxxx>]

In qcom_smem_state_register() and qcom_smem_state_release(), we
should better use of_node_get() and of_node_put() for the reference
creation and destruction of 'device_node'.

Fixes: 9460ae2ff308 ("soc: qcom: Introduce common SMEM state machine code")
Signed-off-by: Liang He <windhl@xxxxxxx>
---
I have learned that the 'state->of_node' is used to match client
lookups. But I do not know if there will be a premature free or UAF
if we do not refcount this new reference created in to 'state->of_node'.
Please check it carefully.


 drivers/soc/qcom/smem_state.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/smem_state.c b/drivers/soc/qcom/smem_state.c
index 31faf4aa868e..e848cc9a3cf8 100644
--- a/drivers/soc/qcom/smem_state.c
+++ b/drivers/soc/qcom/smem_state.c
@@ -136,6 +136,7 @@ static void qcom_smem_state_release(struct kref *ref)
 	struct qcom_smem_state *state = container_of(ref, struct qcom_smem_state, refcount);
 
 	list_del(&state->list);
+	of_node_put(state->of_node);
 	kfree(state);
 }
 
@@ -205,7 +206,7 @@ struct qcom_smem_state *qcom_smem_state_register(struct device_node *of_node,
 
 	kref_init(&state->refcount);
 
-	state->of_node = of_node;
+	state->of_node = of_node_get(of_node);
 	state->ops = *ops;
 	state->priv = priv;
 
-- 
2.25.1