From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heikki Krogerus Subject: [PATCH v3 01/10] usb: typec: Take care of driver module reference counting Date: Tue, 4 Sep 2018 14:22:10 +0300 Message-ID: <20180904112219.89287-2-heikki.krogerus@linux.intel.com> References: <20180904112219.89287-1-heikki.krogerus@linux.intel.com> Return-path: In-Reply-To: <20180904112219.89287-1-heikki.krogerus@linux.intel.com> Sender: stable-owner@vger.kernel.org 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 List-Id: platform-driver-x86.vger.kernel.org Functions typec_mux_get() and typec_switch_get() already make sure that the mux device reference count is incremented, but the same must be done to the driver module as well to prevent the drivers from being unloaded in the middle of operation. This fixes a potential "BUG: unable to handle kernel paging request at ..." from happening. Fixes: 93dd2112c7b2 ("usb: typec: mux: Get the mux identifier from function parameter") Cc: Signed-off-by: Heikki Krogerus --- drivers/usb/typec/mux.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/usb/typec/mux.c b/drivers/usb/typec/mux.c index ddaac63ecf12..d990aa510fab 100644 --- a/drivers/usb/typec/mux.c +++ b/drivers/usb/typec/mux.c @@ -9,6 +9,7 @@ #include #include +#include #include #include @@ -49,8 +50,10 @@ struct typec_switch *typec_switch_get(struct device *dev) mutex_lock(&switch_lock); sw = device_connection_find_match(dev, "typec-switch", NULL, typec_switch_match); - if (!IS_ERR_OR_NULL(sw)) + if (!IS_ERR_OR_NULL(sw)) { + WARN_ON(!try_module_get(sw->dev->driver->owner)); get_device(sw->dev); + } mutex_unlock(&switch_lock); return sw; @@ -65,8 +68,10 @@ EXPORT_SYMBOL_GPL(typec_switch_get); */ void typec_switch_put(struct typec_switch *sw) { - if (!IS_ERR_OR_NULL(sw)) + if (!IS_ERR_OR_NULL(sw)) { + module_put(sw->dev->driver->owner); put_device(sw->dev); + } } EXPORT_SYMBOL_GPL(typec_switch_put); @@ -136,8 +141,10 @@ struct typec_mux *typec_mux_get(struct device *dev, const char *name) mutex_lock(&mux_lock); mux = device_connection_find_match(dev, name, NULL, typec_mux_match); - if (!IS_ERR_OR_NULL(mux)) + if (!IS_ERR_OR_NULL(mux)) { + WARN_ON(!try_module_get(mux->dev->driver->owner)); get_device(mux->dev); + } mutex_unlock(&mux_lock); return mux; @@ -152,8 +159,10 @@ EXPORT_SYMBOL_GPL(typec_mux_get); */ void typec_mux_put(struct typec_mux *mux) { - if (!IS_ERR_OR_NULL(mux)) + if (!IS_ERR_OR_NULL(mux)) { + module_put(mux->dev->driver->owner); put_device(mux->dev); + } } EXPORT_SYMBOL_GPL(typec_mux_put); -- 2.18.0