USB: cdc-wdm: poll must return POLLHUP if device is gone

Else the poll will be restarted indefinitely in a tight loop,
preventing final device cleanup.

Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 5d15165..7652275 100644 (file)
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -548,7 +548,7 @@ static unsigned int wdm_poll(struct file *file, struct poll_table_struct *wait)
 
        spin_lock_irqsave(&desc->iuspin, flags);
        if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
-               mask = POLLERR;
+               mask = POLLHUP | POLLERR;
                spin_unlock_irqrestore(&desc->iuspin, flags);
                goto desc_out;
        }