[030/139] HID: fix oops in gyration_event()

[Greg KH]

2.6.33-stable review patch.  If anyone has any objections, please let us know.

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

From: Jiri Kosina <jkosina@xxxxxxx>

commit d8e4ebf8b603bdcd091540e6b5bddf0dec10d516 upstream.

Fix oops caused by dereferencing field->hidinput in cases where
the device hasn't been claimed by hid-input.

Reported-by: Andreas Demmer <mail@xxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/hid/hid-gyration.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/hid/hid-gyration.c
+++ b/drivers/hid/hid-gyration.c
@@ -53,10 +53,13 @@ static int gyration_input_mapping(struct
 static int gyration_event(struct hid_device *hdev, struct hid_field *field,
 		struct hid_usage *usage, __s32 value)
 {
-	struct input_dev *input = field->hidinput->input;
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput)
+		return 0;
 
 	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_GENDESK &&
 			(usage->hid & 0xff) == 0x82) {
+		struct input_dev *input = field->hidinput->input;
 		input_event(input, usage->type, usage->code, 1);
 		input_sync(input);
 		input_event(input, usage->type, usage->code, 0);


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