of: handle NULL node in next_child iterators

Add an early check for the node argument in __of_get_next_child and
of_get_next_available_child() to avoid dereferencing a NULL node pointer
a few lines after.

CC: Daniel Mack <zonque@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Grant Likely <grant.likely@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index e67b308819c9..567e6e1b7921 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -700,6 +700,9 @@ static struct device_node *__of_get_next_child(const struct device_node *node,
 {
         struct device_node *next;
 
+        if (!node)
+                return NULL;
+
         next = prev ? prev->sibling : node->child;
         for (; next; next = next->sibling)
                 if (of_node_get(next))
@@ -746,6 +749,9 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
         struct device_node *next;
         unsigned long flags;
 
+        if (!node)
+                return NULL;
+
         raw_spin_lock_irqsave(&devtree_lock, flags);
         next = prev ? prev->sibling : node->child;
         for (; next; next = next->sibling) {