[097/119] hso: fix soft-lockup

[Greg KH]

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Antti Kaijanmäki <antti.kaijanmaki@xxxxxxxxxxx>

commit dcfcb256cc23c4436691b0fe677275306699d6a1 upstream.

Fix soft-lockup in hso.c which is triggered on SMP machine when
modem is removed while file descriptor(s) under /dev are still open:

  old version called kref_put() too early which resulted in destroying
  hso_serial and hso_device objects which were still used later on.

Signed-off-by: Antti Kaijanmäki <antti.kaijanmaki@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>

---
 drivers/net/usb/hso.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1362,7 +1362,7 @@ static void hso_serial_close(struct tty_
 	/* reset the rts and dtr */
 	/* do the actual close */
 	serial->open_count--;
-	kref_put(&serial->parent->ref, hso_serial_ref_free);
+
 	if (serial->open_count <= 0) {
 		serial->open_count = 0;
 		spin_lock_irq(&serial->serial_lock);
@@ -1382,6 +1382,8 @@ static void hso_serial_close(struct tty_
 		usb_autopm_put_interface(serial->parent->interface);
 
 	mutex_unlock(&serial->parent->mutex);
+
+	kref_put(&serial->parent->ref, hso_serial_ref_free);
 }
 
 /* close the requested serial port */


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