device property: Fix usecount for of_graph_get_port_parent()

Fix inconsistent use of of_graph_get_port_parent() where
asoc_simple_card_parse_graph_dai() does of_node_get() before
calling it while other callers do not. We can fix this by
not trashing the node passed to of_graph_get_port_parent().

Let's also make sure the callers have correct refcounts and remove
related incorrect of_node_put() calls for of_for_each_phandle
as that's done by of_phandle_iterator_next() except when
we break out of the loop early.

Let's fix both issues with a single patch to avoid kobject
refcounts getting messed up more if two patches are merged
separately.

Otherwise strange issues can happen caused by memory corruption
caused by too many kobject_del() calls such as:

BUG: sleeping function called from invalid context at
kernel/locking/mutex.c:747
...
(___might_sleep)
(__mutex_lock)
(mutex_lock_nested)
(kernfs_remove)
(kobject_del)
(kobject_put)
(of_get_next_parent)
(of_graph_get_port_parent)
(asoc_simple_card_parse_graph_dai [snd_soc_simple_card_utils])
(asoc_graph_card_probe [snd_soc_audio_graph_card])

Fixes: 0ef472a973eb ("of_graph: add of_graph_get_port_parent()")
Fixes: 2692c1c63c29 ("ASoC: add audio-graph-card support")
Fixes: 1689333f8311 ("ASoC: simple-card-utils: add asoc_simple_card_parse_graph_dai()")
Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Tested-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/of/property.c b/drivers/of/property.c
index eda50b4be9349d26c5600a19426cdc1d7f7fe92b..067f9fab7b77c7945d40b7646b443bb8412bf01f 100644 (file)
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -708,6 +708,15 @@ struct device_node *of_graph_get_port_parent(struct device_node *node)
 {
        unsigned int depth;
 
+       if (!node)
+               return NULL;
+
+       /*
+        * Preserve usecount for passed in node as of_get_next_parent()
+        * will do of_node_put() on it.
+        */
+       of_node_get(node);
+
        /* Walk 3 levels up only if there is 'ports' node. */
        for (depth = 3; depth && node; depth--) {
                node = of_get_next_parent(node);
@@ -728,12 +737,16 @@ EXPORT_SYMBOL(of_graph_get_port_parent);
 struct device_node *of_graph_get_remote_port_parent(
                               const struct device_node *node)
 {
-       struct device_node *np;
+       struct device_node *np, *pp;
 
        /* Get remote endpoint node. */
        np = of_graph_get_remote_endpoint(node);
 
-       return of_graph_get_port_parent(np);
+       pp = of_graph_get_port_parent(np);
+
+       of_node_put(np);
+
+       return pp;
 }
 EXPORT_SYMBOL(of_graph_get_remote_port_parent);
 

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index 105ec3a6e30df8340d62d1be45e1bb8577956672..de2550c7a96b095d33e449232087ef2d3b6e4655 100644 (file)
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -224,9 +224,11 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
 
        of_for_each_phandle(&it, rc, node, "dais", NULL, 0) {
                ret = asoc_graph_card_dai_link_of(it.node, priv, idx++);
-               of_node_put(it.node);
-               if (ret < 0)
+               if (ret < 0) {
+                       of_node_put(it.node);
+
                        return ret;
+               }
        }
 
        return asoc_simple_card_parse_card_name(card, NULL);
@@ -239,10 +241,8 @@ static int asoc_graph_get_dais_count(struct device *dev)
        int count = 0;
        int rc;
 
-       of_for_each_phandle(&it, rc, node, "dais", NULL, 0) {
+       of_for_each_phandle(&it, rc, node, "dais", NULL, 0)
                count++;
-               of_node_put(it.node);
-       }
 
        return count;
 }

diff --git a/sound/soc/generic/audio-graph-scu-card.c b/sound/soc/generic/audio-graph-scu-card.c
index dcd2df37bc3bfbd78e1f0d7bbb50b5192a89cc2d..758ac06f3a99413c5dffffbfe747d6c14c4f3a9c 100644 (file)
--- a/sound/soc/generic/audio-graph-scu-card.c
+++ b/sound/soc/generic/audio-graph-scu-card.c
@@ -215,7 +215,6 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
                codec_ep = of_graph_get_remote_endpoint(cpu_ep);
                rcpu_ep  = of_graph_get_remote_endpoint(codec_ep);
 
-               of_node_put(cpu_port);
                of_node_put(cpu_ep);
                of_node_put(codec_ep);
                of_node_put(rcpu_ep);
@@ -232,8 +231,10 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
 
                ret = asoc_simple_card_parse_daifmt(dev, cpu_ep, codec_ep,
                                                            NULL, &daifmt);
-               if (ret < 0)
+               if (ret < 0) {
+                       of_node_put(cpu_port);
                        goto parse_of_err;
+               }
        }
 
        dai_idx = 0;
@@ -250,7 +251,6 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
                        codec_ep = of_graph_get_remote_endpoint(cpu_ep);
                        codec_port = of_graph_get_port_parent(codec_ep);
 
-                       of_node_put(cpu_port);
                        of_node_put(cpu_ep);
                        of_node_put(codec_ep);
                        of_node_put(codec_port);
@@ -266,13 +266,17 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
 
                                /* Back-End (= Codec) */
                                ret = asoc_graph_card_dai_link_of(codec_ep, priv, daifmt, dai_idx++, 0);
-                               if (ret < 0)
+                               if (ret < 0) {
+                                       of_node_put(cpu_port);
                                        goto parse_of_err;
+                               }
                        } else {
                                /* Front-End (= CPU) */
                                ret = asoc_graph_card_dai_link_of(cpu_ep, priv, daifmt, dai_idx++, 1);
-                               if (ret < 0)
+                               if (ret < 0) {
+                                       of_node_put(cpu_port);
                                        goto parse_of_err;
+                               }
                        }
                }
        }
@@ -306,7 +310,6 @@ static int asoc_graph_get_dais_count(struct device *dev)
                codec_ep = of_graph_get_remote_endpoint(cpu_ep);
                codec_port = of_graph_get_port_parent(codec_ep);
 
-               of_node_put(cpu_port);
                of_node_put(cpu_ep);
                of_node_put(codec_ep);
                of_node_put(codec_port);

diff --git a/sound/soc/generic/simple-card-utils.c b/sound/soc/generic/simple-card-utils.c
index 26d64fa40c9cf1438f43a08d8f45b15ac0184fa9..7d7ab4aee42e3ab133926f2dc5b11489b93a28ae 100644 (file)
--- a/sound/soc/generic/simple-card-utils.c
+++ b/sound/soc/generic/simple-card-utils.c
@@ -263,6 +263,9 @@ static int asoc_simple_card_get_dai_id(struct device_node *ep)
                        id = i;
                i++;
        }
+
+       of_node_put(node);
+
        if (id < 0)
                return -ENODEV;
 
@@ -282,11 +285,6 @@ int asoc_simple_card_parse_graph_dai(struct device_node *ep,
        if (!dai_name)
                return 0;
 
-       /*
-        * of_graph_get_port_parent() will call
-        * of_node_put(). So, call of_node_get() here
-        */
-       of_node_get(ep);
        node = of_graph_get_port_parent(ep);
 
        /* Get dai->name */

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 921622a019448394687655034f52befb4abfd6ec..0cf8498fa36c86371a0aa16939cb00977ce190ef 100644 (file)
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -4113,6 +4113,8 @@ int snd_soc_get_dai_id(struct device_node *ep)
        }
        mutex_unlock(&client_mutex);
 
+       of_node_put(node);
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(snd_soc_get_dai_id);