[3.11.y.z extended stable] Patch "USB: sierra: fix AA deadlock in open error path" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    USB: sierra: fix AA deadlock in open error path

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b93e8a54aa19279a3a2c1250c6af859e3e0c2c2c Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold at gmail.com>
Date: Mon, 26 May 2014 19:22:50 +0200
Subject: USB: sierra: fix AA deadlock in open error path

commit 353fe198602e8b4d1c7bdcceb8e60955087201b1 upstream.

Fix AA deadlock in open error path that would call close() and try to
grab the already held disc_mutex.

Fixes: b9a44bc19f48 ("sierra: driver urb handling improvements")

Signed-off-by: Johan Hovold <jhovold at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/serial/sierra.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index b6910b7ab7e2..b3f2b60465bd 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -824,14 +824,9 @@ static int sierra_open(struct tty_struct *tty, struct usb_serial_port *port)
 			usb_sndbulkpipe(serial->dev, endpoint) | USB_DIR_IN);

 	err = sierra_submit_rx_urbs(port, GFP_KERNEL);
-	if (err) {
-		/* get rid of everything as in close */
-		sierra_close(port);
-		/* restore balance for autopm */
-		if (!serial->disconnected)
-			usb_autopm_put_interface(serial->interface);
-		return err;
-	}
+	if (err)
+		goto err_submit;
+
 	sierra_send_setup(port);

 	serial->interface->needs_remote_wakeup = 1;
@@ -841,6 +836,16 @@ static int sierra_open(struct tty_struct *tty, struct usb_serial_port *port)
 	usb_autopm_put_interface(serial->interface);

 	return 0;
+
+err_submit:
+	sierra_stop_rx_urbs(port);
+
+	for (i = 0; i < portdata->num_in_urbs; i++) {
+		sierra_release_urb(portdata->in_urbs[i]);
+		portdata->in_urbs[i] = NULL;
+	}
+
+	return err;
 }


--
1.9.1