usb: misc: usbtest: add fix for driver hang

In sg_timeout(), req->status is set to "-ETIMEDOUT" before calling
into usb_sg_cancel(). usb_sg_cancel() will do nothing and return
directly if req->status has been set to a non-zero value. This will
cause driver hang whenever transfer time out is triggered.

This patch fixes this issue. It could be backported to stable kernel
with version later than v3.15.

Cc: stable@vger.kernel.org # 3.15+
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index 5e3464e8d4e5aa2796dc1385ac81f8f705cf5128..5c8210dc6fd9cf9c0b39003d92b59a1440ddb0c2 100644 (file)
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -585,7 +585,6 @@ static void sg_timeout(unsigned long _req)
 {
        struct usb_sg_request   *req = (struct usb_sg_request *) _req;
 
-       req->status = -ETIMEDOUT;
        usb_sg_cancel(req);
 }
 
@@ -616,8 +615,10 @@ static int perform_sglist(
                mod_timer(&sg_timer, jiffies +
                                msecs_to_jiffies(SIMPLE_IO_TIMEOUT));
                usb_sg_wait(req);
-               del_timer_sync(&sg_timer);
-               retval = req->status;
+               if (!del_timer_sync(&sg_timer))
+                       retval = -ETIMEDOUT;
+               else
+                       retval = req->status;
 
                /* FIXME check resulting data pattern */