| Message ID | 20210409124136.65591-1-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 3a2a91a2d51761557843996a66098eb7182b48b4 |
| Headers | show |
| Series | [v2] usb: roles: Call try_module_get() from usb_role_switch_find_by_fwnode() | expand |
On Fri, Apr 09, 2021 at 02:41:36PM +0200, Hans de Goede wrote: > usb_role_switch_find_by_fwnode() returns a reference to the role-switch > which must be put by calling usb_role_switch_put(). > > usb_role_switch_put() calls module_put(sw->dev.parent->driver->owner), > add a matching try_module_get() to usb_role_switch_find_by_fwnode(), > making it behave the same as the other usb_role_switch functions > which return a reference. > > This avoids a WARN_ON being hit at kernel/module.c:1158 due to the > module-refcount going below 0. > > Fixes: c6919d5e0cd1 ("usb: roles: Add usb_role_switch_find_by_fwnode()") > Reviewed-by: Guenter Roeck <linux@roeck-us.net> > Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> > --- > Changes in v2: > - Fix typo in Subject > - Add Fixes tag > --- > drivers/usb/roles/class.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c > index 97f37077b7f9..33b637d0d8d9 100644 > --- a/drivers/usb/roles/class.c > +++ b/drivers/usb/roles/class.c > @@ -189,6 +189,8 @@ usb_role_switch_find_by_fwnode(const struct fwnode_handle *fwnode) > return NULL; > > dev = class_find_device_by_fwnode(role_class, fwnode); > + if (dev) > + WARN_ON(!try_module_get(dev->parent->driver->owner)); > > return dev ? to_role_switch(dev) : NULL; > } > -- > 2.30.2 thanks,
diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c index 97f37077b7f9..33b637d0d8d9 100644 --- a/drivers/usb/roles/class.c +++ b/drivers/usb/roles/class.c @@ -189,6 +189,8 @@ usb_role_switch_find_by_fwnode(const struct fwnode_handle *fwnode) return NULL; dev = class_find_device_by_fwnode(role_class, fwnode); + if (dev) + WARN_ON(!try_module_get(dev->parent->driver->owner)); return dev ? to_role_switch(dev) : NULL; }
usb_role_switch_find_by_fwnode() returns a reference to the role-switch which must be put by calling usb_role_switch_put(). usb_role_switch_put() calls module_put(sw->dev.parent->driver->owner), add a matching try_module_get() to usb_role_switch_find_by_fwnode(), making it behave the same as the other usb_role_switch functions which return a reference. This avoids a WARN_ON being hit at kernel/module.c:1158 due to the module-refcount going below 0. Fixes: c6919d5e0cd1 ("usb: roles: Add usb_role_switch_find_by_fwnode()") Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Hans de Goede <hdegoede@redhat.com> --- Changes in v2: - Fix typo in Subject - Add Fixes tag --- drivers/usb/roles/class.c | 2 ++ 1 file changed, 2 insertions(+)