[PATCH 1/5] USB: cdc-acm: fix device unregistration

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
---
 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 8ac25ad..e18e9a8 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -593,7 +593,6 @@ 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);
@@ -1411,6 +1410,8 @@ 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);
-- 
1.8.1.1

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Media]     [Linux Input]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Old Linux USB Devel Archive]

  Powered by Linux