[044/119] USB: cdc_acm: Fix race condition when opening tty

[Greg KH]

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

------------------
From: Henry Gebhardt <gebhardt@xxxxxxxxxxxxxxxxxxxxxx>

commit 18a77b5d237a67d2c621a46f5271a3b51da1b380 upstream.

If acm_rx_tasklet() gets called before tty_port_block_til_ready()
returns, then bulk IN urbs may not be sent. This fixes it.

Signed-off-by: Henry Gebhardt <gebhardt@xxxxxxxxxxxxxxxxxxxxxx>
Acked-by: Oliver Neukum <oliver@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/usb/class/cdc-acm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -609,9 +609,9 @@ static int acm_tty_open(struct tty_struc
 
 	acm->throttle = 0;
 
-	tasklet_schedule(&acm->urb_task);
 	set_bit(ASYNCB_INITIALIZED, &acm->port.flags);
 	rv = tty_port_block_til_ready(&acm->port, tty, filp);
+	tasklet_schedule(&acm->urb_task);
 done:
 	mutex_unlock(&acm->mutex);
 err_out:


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