[POWERPC] Add null pointer check to of_find_property

Update function of_find_property() to return NULL if the device_node
passed to it is also NULL.  Otherwise, passing NULL will cause a null
pointer dereference.

Without this, the legacy_serial driver will crash if there's no
'chosen' node in the device tree.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 9bd7c4a31253..23ffb7c0caf2 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -65,6 +65,9 @@ struct property *of_find_property(const struct device_node *np,
 {
         struct property *pp;
 
+        if (!np)
+                return NULL;
+
         read_lock(&devtree_lock);
         for (pp = np->properties; pp != 0; pp = pp->next) {
                 if (of_prop_cmp(pp->name, name) == 0) {