HI,

On 04-09-18 13:22, Heikki Krogerus wrote:

This fixes potential "BUG: unable to handle kernel paging request at ..." from happening.

Fixes: fde0aa6c175a ("usb: common: Small class for USB role switches") Cc: stable@vger.kernel.org Signed-off-by: Heikki Krogerus heikki.krogerus@linux.intel.com

---

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..3d8a776e55ee 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(sw))

• WARN_ON(!try_module_get(sw->dev.parent->driver->owner));
  

While testing I found a bug, so sorry but this is going to need a v4, device_connection_find_match() may return NULL here, so this needs to be if (!IS_ERR_OR_NULL(sw)) to avoid an oops.

Note I'm also seeing some other issues which I need to debug I will do so tomorrow morning so you may want to wait a bit with v4.

Regards,

Hans

• 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);