This is a note to let you know that I've just added the patch titled
USB: cdc-acm: fix device unregistration
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-cdc-acm-fix-device-unregistration.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cb25505fc604292c70fc02143fc102f54c8595f0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Tue, 19 Mar 2013 09:21:06 +0100
Subject: USB: cdc-acm: fix device unregistration
From: Johan Hovold <jhovold@xxxxxxxxx>
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.
Acked-by: Oliver Neukum <oneukum@xxxxxxx>
Cc: Oliver Neukum <oneukum@xxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/class/cdc-acm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- 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
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_in
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);
Patches currently in stable-queue which might be from jhovold@xxxxxxxxx are
queue-3.4/usb-cdc-acm-fix-device-unregistration.patch
queue-3.4/usb-serial-fix-interface-refcounting.patch
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