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

commit 616b6937e348ef2b4c6ea5fef2cd3c441145efb0 upstream.

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

Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index cfe5be4..38d8c33 100644 (file)
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -511,7 +511,7 @@ 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)) {
 
        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;
        }
                spin_unlock_irqrestore(&desc->iuspin, flags);
                goto desc_out;
        }