linux-kernel - [PATCH 37/79] tty: USB hangup is racy

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Date:	Sat, 19 Sep 2009 14:36:42 -0700
From:	Greg Kroah-Hartman <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org
Cc:	Alan Cox <alan@...ux.intel.com>, stable <stable@...nel.org>,
	Greg Kroah-Hartman <gregkh@...e.de>
Subject: [PATCH 37/79] tty: USB hangup is racy

From: Alan Cox <alan@...ux.intel.com>

The USB layer uses tty_hangup to deal with unplugs of the physical hardware
(analogous to loss of carrier) and then frees the resources. However the
tty_hangup is asynchronous. As the hangup can sleep we can use tty_vhangup
which is the non async version to avoid freeing resources too early.

Signed-off-by: Alan Cox <alan@...ux.intel.com>
Cc: stable <stable@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
 drivers/usb/serial/usb-serial.c |    5 +----
 1 files changed, 1 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 99188c9..21dd72a 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1161,10 +1161,7 @@ void usb_serial_disconnect(struct usb_interface *interface)
 		if (port) {
 			struct tty_struct *tty = tty_port_tty_get(&port->port);
 			if (tty) {
-				/* The hangup will occur asynchronously but
-				   the object refcounts will sort out all the
-				   cleanup */
-				tty_hangup(tty);
+				tty_vhangup(tty);
 				tty_kref_put(tty);
 			}
 			kill_traffic(port);
-- 
1.6.4.2

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