Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Wed, 23 Nov 2022 20:00:14 +0100 | Subject | Re: [PATCH] powercap: fix possible name leak while device_register() fails |
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On Sat, Nov 12, 2022 at 10:42 AM Yang Yingliang <yangyingliang@huawei.com> wrote: > > If device_register() returns error, the name allocated by > dev_set_name() need be freed. In technical, we should call > put_device() to give up the reference and free the name in > driver core, but in some cases the device is not intizalized, > put_device() can not be called, so don't complicate the code, > just call kfree_const() to free name in the error path. > > Fixes: 75d2364ea0ca ("PowerCap: Add class driver") > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > --- > drivers/powercap/powercap_sys.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/powercap/powercap_sys.c b/drivers/powercap/powercap_sys.c > index f0654a932b37..11e742dc83b9 100644 > --- a/drivers/powercap/powercap_sys.c > +++ b/drivers/powercap/powercap_sys.c > @@ -572,6 +572,7 @@ struct powercap_zone *powercap_register_zone( > err_name_alloc: > idr_remove(power_zone->parent_idr, power_zone->id); > err_idr_alloc: > + kfree_const(dev_name(&power_zone->dev)); > if (power_zone->allocated) > kfree(power_zone); > mutex_unlock(&control_type->lock); > @@ -622,6 +623,7 @@ struct powercap_control_type *powercap_register_control_type( > dev_set_name(&control_type->dev, "%s", name); > result = device_register(&control_type->dev); > if (result) { > + kfree_const(dev_name(&control_type->dev));
Why is it necessary to free a device name explicitly after a failing device_register()?
If it is really necessary, then there is a problem in device_register() itself AFAICS, because it uses dev_set_name() at least in the dev->init_name present case.
> if (control_type->allocated) > kfree(control_type); > return ERR_PTR(result); > --
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