[3.8.y.z extended stable] Patch "USB: usb_wwan: fix handling of missing bulk endpoints" has been added to staging queue

[Kamal Mostafa]

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

    USB: usb_wwan: fix handling of missing bulk endpoints

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.24.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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>From 365724351d1c0bd2c22748ee9d3b5df2ceed5b11 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold at gmail.com>
Date: Thu, 3 Apr 2014 13:06:46 +0200
Subject: USB: usb_wwan: fix handling of missing bulk endpoints
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit bd73bd8831696f189a479a0712ae95208e513d7e upstream.

Fix regression introduced by commit 8e493ca1767d ("USB: usb_wwan: fix
bulk-urb allocation") by making sure to require both bulk-in and out
endpoints during port probe.

The original option driver (which usb_wwan is based on) was written
under the assumption that either endpoint could be missing, but
evidently this cannot have been tested properly. Specifically, it would
handle opening a device without bulk-in (but would blow up during resume
which was implemented later), but not a missing bulk-out in write()
(although it is handled in some places such as write_room()).

Fortunately (?), the driver also got the test for missing endpoints
wrong so the urbs were in fact always allocated, although they would be
initialised using the wrong endpoint address (0) and any submission of
such an urb would fail.

The commit mentioned above fixed the test for missing endpoints but
thereby exposed the other bugs which would now generate null-pointer
exceptions rather than failed urb submissions.

The regression was introduced in v3.7, but the offending commit was also
marked for stable.

Reported-by: Rafał Miłecki <zajec5 at gmail.com>
Signed-off-by: Johan Hovold <jhovold at gmail.com>
Tested-by: Rafał Miłecki <zajec5 at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/serial/usb_wwan.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c
index c9691c8..7dca098 100644
--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -476,6 +476,9 @@ int usb_wwan_port_probe(struct usb_serial_port *port)
 	int err;
 	int i;

+	if (!port->bulk_in_size || !port->bulk_out_size)
+		return -ENODEV;
+
 	portdata = kzalloc(sizeof(*portdata), GFP_KERNEL);
 	if (!portdata)
 		return -ENOMEM;
@@ -483,9 +486,6 @@ int usb_wwan_port_probe(struct usb_serial_port *port)
 	init_usb_anchor(&portdata->delayed);

 	for (i = 0; i < N_IN_URB; i++) {
-		if (!port->bulk_in_size)
-			break;
-
 		buffer = (u8 *)__get_free_page(GFP_KERNEL);
 		if (!buffer)
 			goto bail_out_error;
@@ -499,9 +499,6 @@ int usb_wwan_port_probe(struct usb_serial_port *port)
 	}

 	for (i = 0; i < N_OUT_URB; i++) {
-		if (!port->bulk_out_size)
-			break;
-
 		buffer = kmalloc(OUT_BUFLEN, GFP_KERNEL);
 		if (!buffer)
 			goto bail_out_error2;
--
1.9.1