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authorTony Lindgren <tony@atomide.com>2017-07-28 11:23:15 +0300
committerMark Brown <broonie@kernel.org>2017-08-01 17:15:42 +0300
commitc0a480d1acf7dc184f9f3e7cf724483b0d28dc2e (patch)
tree0c4d178bc64d97ba035fa18a91ad519f2c670717 /drivers/of
parent5771a8c08880cdca3bfb4a3fc6d309d6bba20877 (diff)
downloadlinux-c0a480d1acf7dc184f9f3e7cf724483b0d28dc2e.tar.xz
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>
Diffstat (limited to 'drivers/of')
-rw-r--r--drivers/of/property.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/of/property.c b/drivers/of/property.c
index eda50b4be934..067f9fab7b77 100644
--- 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);