[PATCH 4.9 019/130] usb: gadget: composite: fix delayed_status race condition when set_interface

Greg Kroah-Hartman
2018-08-23T08:07:33Z

From: Chunfeng Yun <chunfeng.yun@mediatek.com>

[ Upstream commit 980900d6318066b9f8314bfb87329a20fd0d1ca4 ]

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.yun@mediatek.com>
Tested-by: Jay Hsu <shih-chieh.hsu@mediatek.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/composite.c | 3 +++
1 file changed, 3 insertions(+)

--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1712,6 +1712,8 @@ composite_setup(struct usb_gadget *gadge
*/
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,
@@ -1721,6 +1723,7 @@ composite_setup(struct usb_gadget *gadge
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))