ASoC: audio-graph-card: fix an use-after-free in graph_get_dai_id()

After calling of_node_put() on the node variable, it is still being
used, which may result in use-after-free.
Fix this issue by calling of_node_put() after the last usage.

Fixes: a0c426fe1433 ("ASoC: simple-card-utils: check "reg" property on asoc_simple_card_get_dai_id()")
Link: https://lore.kernel.org/r/1562743509-30496-5-git-send-email-wen.yang99@zte.com.cn
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index bddfcfd7bedf..343ede8042c3 100644
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -63,6 +63,7 @@ static int graph_get_dai_id(struct device_node *ep)
         struct device_node *endpoint;
         struct of_endpoint info;
         int i, id;
+        u32 *reg;
         int ret;
 
         /* use driver specified DAI ID if exist */
@@ -83,8 +84,9 @@ static int graph_get_dai_id(struct device_node *ep)
                         return info.id;
 
                 node = of_get_parent(ep);
+                reg = of_get_property(node, "reg", NULL);
                 of_node_put(node);
-                if (of_get_property(node, "reg", NULL))
+                if (reg)
                         return info.port;
         }
         node = of_graph_get_port_parent(ep);