From patchwork Thu Jul 23 21:30:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bastien Nocera X-Patchwork-Id: 11681651 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7B58B6C1 for ; Thu, 23 Jul 2020 21:30:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69522207C4 for ; Thu, 23 Jul 2020 21:30:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726861AbgGWVam (ORCPT ); Thu, 23 Jul 2020 17:30:42 -0400 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:37855 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726368AbgGWVam (ORCPT ); Thu, 23 Jul 2020 17:30:42 -0400 X-Originating-IP: 82.255.60.242 Received: from classic (lns-bzn-39-82-255-60-242.adsl.proxad.net [82.255.60.242]) (Authenticated sender: hadess@hadess.net) by relay6-d.mail.gandi.net (Postfix) with ESMTPSA id 27F1DC0008; Thu, 23 Jul 2020 21:30:39 +0000 (UTC) Message-ID: Subject: [PATCH v3] USB: Fix device driver race From: Bastien Nocera To: linux-usb@vger.kernel.org Cc: Greg Kroah-Hartman , Alan Stern Date: Thu, 23 Jul 2020 23:30:39 +0200 User-Agent: Evolution 3.36.3 (3.36.3-1.fc32) MIME-Version: 1.0 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org When a new device with a specialised device driver is plugged in, the new driver will be modprobe()'d but the driver core will attach the "generic" driver to the device. After that, nothing will trigger a reprobe when the modprobe()'d device driver has finished initialising, as the device has the "generic" driver attached to it. Trigger a reprobe ourselves when new specialised drivers get registered. Fixes: 88b7381a939d Signed-off-by: Bastien Nocera Reported-by: kernel test robot Reported-by: kernel test robot --- Changes since v2: - Fix formatting Changes since v1: - Simplified after Alan Stern's comments and some clarifications from Benjamin Tissoires. drivers/usb/core/driver.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index f81606c6a35b..44531910637c 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -905,6 +905,25 @@ static int usb_uevent(struct device *dev, struct kobj_uevent_env *env) return 0; } +static int __usb_bus_reprobe_drivers(struct device *dev, void *data) +{ + struct usb_device_driver *udriver = to_usb_device_driver(dev->driver); + struct usb_device *udev = to_usb_device(dev); + + if (dev->driver) { + struct usb_device_driver *udriver = to_usb_device_driver(dev->driver); + + if (udriver == NULL || udriver == &usb_generic_driver) { + udev->use_generic_driver = false; + device_reprobe(dev); + } + } else { + device_reprobe(dev); + } + + return 0; +} + /** * usb_register_device_driver - register a USB device (not interface) driver * @new_udriver: USB operations for the device driver @@ -934,13 +953,19 @@ int usb_register_device_driver(struct usb_device_driver *new_udriver, retval = driver_register(&new_udriver->drvwrap.driver); - if (!retval) + if (!retval) { + /* Check whether any device could be better served with + * this new driver + */ + bus_for_each_dev(&usb_bus_type, NULL, NULL, + __usb_bus_reprobe_drivers); pr_info("%s: registered new device driver %s\n", usbcore_name, new_udriver->name); - else + } else { printk(KERN_ERR "%s: error %d registering device " " driver %s\n", usbcore_name, retval, new_udriver->name); + } return retval; }