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@xxxxxxxxxxxxxxx>
Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
---
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);
