USB: serial: suppress driver bind attributes

BugLink: https://bugs.launchpad.net/bugs/1862259
commit fdb838efa31e1ed9a13ae6ad0b64e30fdbd00570 upstream.

USB-serial drivers must not be unbound from their ports before the
corresponding USB driver is unbound from the parent interface so
suppress the bind and unbind attributes.

Unbinding a serial driver while it's port is open is a sure way to
trigger a crash as any driver state is released on unbind while port
hangup is handled on the parent USB interface level. Drivers for
multiport devices where ports share a resource such as an interrupt
endpoint also generally cannot handle individual ports going away.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 1d7d5f50854be5a3c253b3afaaa5d5c6ee106c1d..2e4527cfe955fc001a337b2919f3fe5bd93c0864 100644 (file)
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1307,6 +1307,9 @@ static int usb_serial_register(struct usb_serial_driver *driver)
                return -EINVAL;
        }
 
+       /* Prevent individual ports from being unbound. */
+       driver->driver.suppress_bind_attrs = true;
+
        usb_serial_operations_init(driver);
 
        /* Add this device to our list of devices */