[PATCH 4.4 44/70] usb: cdc-wdm: Fix a sleep-in-atomic-context bug in service_outstanding_interrupt()

[Greg Kroah-Hartman]

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

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

From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>

commit 6e22e3af7bb3a7b9dc53cb4687659f6e63fca427 upstream.

wdm_in_callback() is a completion handler function for the USB driver.
So it should not sleep. But it calls service_outstanding_interrupt(),
which calls usb_submit_urb() with GFP_KERNEL.

To fix this bug, GFP_KERNEL is replaced with GFP_ATOMIC.

This bug is found by my static analysis tool DSAC.

Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/class/cdc-wdm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -453,7 +453,7 @@ static int clear_wdm_read_flag(struct wd
 
 	set_bit(WDM_RESPONDING, &desc->flags);
 	spin_unlock_irq(&desc->iuspin);
-	rv = usb_submit_urb(desc->response, GFP_KERNEL);
+	rv = usb_submit_urb(desc->response, GFP_ATOMIC);
 	spin_lock_irq(&desc->iuspin);
 	if (rv) {
 		dev_err(&desc->intf->dev,