[PATCH] usb: gadget: composite: fix delayed_status race condition when set_interface

[Chunfeng Yun]

It happens when enable debug log, if set_alt() returns
USB_GADGET_DELAYED_STATUS and usb_composite_setup_continue()
is called before increasing count of @delayed_status,
so fix it by using spinlock of @cdev->lock.

Signed-off-by: Chunfeng Yun <chunfeng....@mediatek.com>
Tested-by: Jay Hsu <shih-chieh....@mediatek.com>
---
 drivers/usb/gadget/composite.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index f242c2b..d2fa071 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1719,6 +1719,8 @@ static int fill_ext_prop(struct usb_configuration *c, int 
interface, u8 *buf)
                 */
                if (w_value && !f->get_alt)
                        break;
+
+               spin_lock(&cdev->lock);
                value = f->set_alt(f, w_index, w_value);
                if (value == USB_GADGET_DELAYED_STATUS) {
                        DBG(cdev,
@@ -1728,6 +1730,7 @@ static int fill_ext_prop(struct usb_configuration *c, int 
interface, u8 *buf)
                        DBG(cdev, "delayed_status count %d\n",
                                        cdev->delayed_status);
                }
+               spin_unlock(&cdev->lock);
                break;
        case USB_REQ_GET_INTERFACE:
                if (ctrl->bRequestType != (USB_DIR_IN|USB_RECIP_INTERFACE))
-- 
1.9.1