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Re: QEMU device refcounting when device creates a container MR
From: |
Igor Mammedov |
Subject: |
Re: QEMU device refcounting when device creates a container MR |
Date: |
Thu, 10 Mar 2022 17:30:53 +0100 |
Do On Thu, 10 Mar 2022 16:05:24 +0000
Peter Maydell <peter.maydell@linaro.org> wrote:
> On Thu, 10 Mar 2022 at 15:36, Igor Mammedov <imammedo@redhat.com> wrote:
> >
> > On Wed, 9 Mar 2022 16:56:21 +0000
> > Peter Maydell <peter.maydell@linaro.org> wrote:
> > > ...also, in the device-introspect-test where I see this problem,
> > > unrealize is never going to be called anyway, because the device
> > > is only put through "instance_init" and then dereffed (which
> > > does not result in instance_finalize being called, because the
> > > refcount is still non-zero).
> >
> > question is why introspected device is deferred instead of being
> > destroyed if it's no longer needed?
>
> ...because the reference count is not zero.
>
> What is supposed to happen is:
> * device is created (inited), and has refcount of 1
> * introspection code does its thing
> * introspection code derefs the device, and it gets deinited
>
> This bug means that when the device is inited it has a refcount
> that is too high, and so despite the code that creates it
> correctly dereffing it, it's still lying around.
looks like ref count leak somewhere, instance_finalize() take care
of cleaning up instance_init() actions.
Do you have an example/reproducer?
> thanks
> -- PMM
>
- QEMU device refcounting when device creates a container MR, Peter Maydell, 2022/03/09
- Re: QEMU device refcounting when device creates a container MR, Paolo Bonzini, 2022/03/09
- Re: QEMU device refcounting when device creates a container MR, Peter Maydell, 2022/03/09
- Re: QEMU device refcounting when device creates a container MR, Peter Maydell, 2022/03/09
- Re: QEMU device refcounting when device creates a container MR, Igor Mammedov, 2022/03/10
- Re: QEMU device refcounting when device creates a container MR, Peter Maydell, 2022/03/10
- Re: QEMU device refcounting when device creates a container MR,
Igor Mammedov <=
- Re: QEMU device refcounting when device creates a container MR, Peter Maydell, 2022/03/10
- Re: QEMU device refcounting when device creates a container MR, Igor Mammedov, 2022/03/18