Re: [Qemu-devel] [PATCH 10/10] qdev: fix create in place obj's life cycle problem

[Paolo Bonzini]

Il 28/08/2012 11:42, Jan Kiszka ha scritto:
> Context A                               Context B
> ---------                               ---------
>                                         object = lookup()
> deregister(object)
> modify(object) -> invalid state
> ...                                     use(object)
> modify(object) -> valid state
> register(object)
> 
> And with "object" I'm not talking about QOM but any data structure.

If you want to avoid locks, the only way to do so is RCU.  Then you do
not modify object at all.

Paolo