From: Alan Stern <stern@rowland.harvard.edu>

Maybe the serial device driver is submitting an URB that is already in
use.  This patch might catch the error.

Cc: <pfmp.404@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/usb/core/urb.c |    6 ++++++
 1 files changed, 6 insertions(+)

diff -puN drivers/usb/core/urb.c~usb-try-to-debug-bug-8561 drivers/usb/core/urb.c
--- a/drivers/usb/core/urb.c~usb-try-to-debug-bug-8561
+++ a/drivers/usb/core/urb.c
@@ -288,6 +288,12 @@ int usb_submit_urb(struct urb *urb, gfp_
 			|| dev->state == USB_STATE_SUSPENDED)
 		return -EHOSTUNREACH;
 
+	/* Not a precise test, but useful for debugging */
+	if (urb->status == -EINPROGRESS) {
+		WARN_ON(1);
+		return -EBUSY;
+	}
+
 	urb->status = -EINPROGRESS;
 	urb->actual_length = 0;
 
_