Thank you for responding.
On 2019/02/18 6:07, Dmitry Torokhov wrote:
> The commit tries to send final uevent for objects for which "add" uevent
> has been sent, but not "remove" event. However in uinput (and general
> input case) we always take care of sending uevent at unregister, and do
> not expect to have uevent sent out at the final "put" time.
Then, we want to keep dev->name and dev->phys when calling "unregister" time.
>
> I believe the real fix is to have kobj->state_remove_uevent_sent be set
> to true as soon as we enter kobject_uevent(kobj, KOBJ_REMOVE) so that
> it is being set even if memory allocation fails. Doing anything else may
> violate expectations of subsystem owning the kobject.
If we want to keep dev->name and dev->phys when calling "unregister" time,
we could do something like below. Does calling kobject_uevent(KOBJ_REMOVE)
without dev->name and dev->phys (to some degree) help (compared to not
triggering kobject_uevent(KOBJ_REMOVE) at all) ?
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 3304aaa..da39a23 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -1587,6 +1587,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
{
struct input_dev *dev = to_input_dev(device);
+ rcu_read_lock();
INPUT_ADD_HOTPLUG_VAR("PRODUCT=%x/%x/%x/%x",
dev->id.bustype, dev->id.vendor,
dev->id.product, dev->id.version);
@@ -1618,6 +1619,7 @@ static int input_dev_uevent(struct device *device, struct kobj_uevent_env *env)
INPUT_ADD_HOTPLUG_BM_VAR("SW=", dev->swbit, SW_MAX);
INPUT_ADD_HOTPLUG_MODALIAS_VAR(dev);
+ rcu_read_unlock();
return 0;
}
diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
index 26ec603f..6689312 100644
--- a/drivers/input/misc/uinput.c
+++ b/drivers/input/misc/uinput.c
@@ -308,9 +308,12 @@ static void uinput_destroy_device(struct uinput_device *udev)
} else {
input_free_device(dev);
}
+ dev->name = NULL;
+ dev->phys = NULL;
+ udev->dev = NULL;
+ synchronize_rcu();
kfree(name);
kfree(phys);
- udev->dev = NULL;
}
}
