[PATCH 3.4 072/134] USB: serial: fix hang when opening port
From: Greg Kroah-Hartman
Date: Thu Apr 10 2014 - 00:11:23 EST
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ming Lei <tom.leiming@xxxxxxxxx>
commit eba0e3c3a0ba7b96f01cbe997680f6a4401a0bfc upstream.
Johan's 'fix use-after-free in TIOCMIWAIT' patchset[1] introduces
one bug which can cause kernel hang when opening port.
This patch initialized the 'port->delta_msr_wait' waitqueue head
to fix the bug which is introduced in 3.9-rc4.
[1], http://marc.info/?l=linux-usb&m=136368139627876&w=2
Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
Acked-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Cc: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/serial/usb-serial.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -908,6 +908,7 @@ int usb_serial_probe(struct usb_interfac
port->port.ops = &serial_port_ops;
port->serial = serial;
spin_lock_init(&port->lock);
+ init_waitqueue_head(&port->delta_msr_wait);
/* Keep this for private driver use for the moment but
should probably go away */
INIT_WORK(&port->work, usb_serial_port_work);
--
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