[PATCH 4.12 61/99] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value()

[Greg Kroah-Hartman]

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>

commit b5212f57da145e53df790a7e211d94daac768bf8 upstream.

acpi_graph_get_child_prop_value() is intended to find a child node with a
certain property value pair. The check

	if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
		continue;

is faulty: fwnode_property_read_u32() returns zero on success, not on
failure, leading to comparing values only if the searched property was not
found.

Moreover, the check is made against the parent device node instead of
the child one as it should be.

Fixes: 79389a83bc38 (ACPI / property: Add support for remote endpoints)
Reported-by: Hyungwoo Yang <hyungwoo.yang@xxxxxxxxx>
Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/acpi/property.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -1046,7 +1046,7 @@ static struct fwnode_handle *acpi_graph_
 	fwnode_for_each_child_node(fwnode, child) {
 		u32 nr;
 
-		if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
+		if (fwnode_property_read_u32(child, prop_name, &nr))
 			continue;
 
 		if (val == nr)