[ 3.5.y.z extended stable ] Patch "USB: cdc-acm: fix device unregistration" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Mon Mar 25 18:02:47 UTC 2013
This is a note to let you know that I have just added a patch titled
USB: cdc-acm: fix device unregistration
to the linux-3.5.y-queue branch of the 3.5.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-3.5.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 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From f184188f3fe1f434f2c0437cb251af0eb33bf25d Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold at gmail.com>
Date: Tue, 19 Mar 2013 09:21:06 +0100
Subject: [PATCH] USB: cdc-acm: fix device unregistration
commit cb25505fc604292c70fc02143fc102f54c8595f0 upstream.
Unregister tty device in disconnect as is required by the USB stack.
By deferring unregistration to when the last tty reference is dropped,
the parent interface device can get unregistered before the child
resulting in broken hotplug events being generated when the tty is
finally closed:
KERNEL[2290.798128] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-1/2-1:3.1 (usb)
KERNEL[2290.804589] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-1 (usb)
KERNEL[2294.554799] remove /2-1:3.1/tty/ttyACM0 (tty)
The driver must deal with tty callbacks after disconnect by checking the
disconnected flag. Specifically, further opens must be prevented and
this is already implemented.
Cc: Oliver Neukum <oneukum at suse.de>
Acked-by: Oliver Neukum <oneukum at suse.de>
Signed-off-by: Johan Hovold <jhovold at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Luis Henriques <luis.henriques at canonical.com>
---
drivers/usb/class/cdc-acm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index ec2bba6..07a9f9c 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -601,7 +601,6 @@ static void acm_port_destruct(struct tty_port *port)
dev_dbg(&acm->control->dev, "%s\n", __func__);
- tty_unregister_device(acm_tty_driver, acm->minor);
acm_release_minor(acm);
usb_put_intf(acm->control);
kfree(acm->country_codes);
@@ -1418,6 +1417,8 @@ static void acm_disconnect(struct usb_interface *intf)
stop_data_traffic(acm);
+ tty_unregister_device(acm_tty_driver, acm->minor);
+
usb_free_urb(acm->ctrlurb);
for (i = 0; i < ACM_NW; i++)
usb_free_urb(acm->wb[i].urb);
--
1.8.1.2
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