On Wed, Mar 04, 2020 at 01:57:39PM -0500, Tejun Heo wrote:

Hey, Greg.

On Wed, Mar 04, 2020 at 06:29:07PM +0100, Greg KH wrote:

quoted

How does that happen?  Who has access to a kobject without also having
the reference count incremented at the same time?  Is this through sysfs
or somewhere within the kernel itself?

Hopefully, this part was addressed in the other reply.

Yes, thanks.

quoted

The struct device refcount should be all that is needed, don't use RCU
just to "delay freeing this object until some later time because someone
else might have a pointer to id".  That's ripe for disaster.

I think it's an idiomatic use of rcu given the circumstances. Whether
the circumstances are reasonable is totally debatable.

They are not reasonable :)