From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga18.intel.com ([134.134.136.126]:19099 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726559AbeIKPJ2 (ORCPT ); Tue, 11 Sep 2018 11:09:28 -0400 From: Heikki Krogerus To: Hans de Goede , Greg Kroah-Hartman Cc: Andy Shevchenko , Darren Hart , platform-driver-x86@vger.kernel.org, linux-usb@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v4 02/10] usb: roles: Handle driver reference counting Date: Tue, 11 Sep 2018 13:10:36 +0300 Message-Id: <20180911101044.44004-3-heikki.krogerus@linux.intel.com> In-Reply-To: <20180911101044.44004-1-heikki.krogerus@linux.intel.com> References: <20180911101044.44004-1-heikki.krogerus@linux.intel.com> Sender: stable-owner@vger.kernel.org List-ID: This fixes potential "BUG: unable to handle kernel paging request at ..." from happening. Fixes: fde0aa6c175a ("usb: common: Small class for USB role switches") Cc: Signed-off-by: Heikki Krogerus --- drivers/usb/common/roles.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/usb/common/roles.c b/drivers/usb/common/roles.c index 15cc76e22123..99116af07f1d 100644 --- a/drivers/usb/common/roles.c +++ b/drivers/usb/common/roles.c @@ -109,8 +109,15 @@ static void *usb_role_switch_match(struct device_connection *con, int ep, */ struct usb_role_switch *usb_role_switch_get(struct device *dev) { - return device_connection_find_match(dev, "usb-role-switch", NULL, - usb_role_switch_match); + struct usb_role_switch *sw; + + sw = device_connection_find_match(dev, "usb-role-switch", NULL, + usb_role_switch_match); + + if (!IS_ERR_OR_NULL(sw)) + WARN_ON(!try_module_get(sw->dev.parent->driver->owner)); + + return sw; } EXPORT_SYMBOL_GPL(usb_role_switch_get); @@ -122,8 +129,10 @@ EXPORT_SYMBOL_GPL(usb_role_switch_get); */ void usb_role_switch_put(struct usb_role_switch *sw) { - if (!IS_ERR_OR_NULL(sw)) + if (!IS_ERR_OR_NULL(sw)) { put_device(&sw->dev); + module_put(sw->dev.parent->driver->owner); + } } EXPORT_SYMBOL_GPL(usb_role_switch_put); -- 2.18.0