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Re: [PATCH 2/6] xive, xics: Fix reference counting on CPU objects
From: |
David Gibson |
Subject: |
Re: [PATCH 2/6] xive, xics: Fix reference counting on CPU objects |
Date: |
Thu, 24 Oct 2019 13:50:41 +1100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
On Wed, Oct 23, 2019 at 04:52:05PM +0200, Greg Kurz wrote:
> When a VCPU gets connected to the XIVE interrupt controller, we add a
> const link targetting the CPU object to the TCTX object. Similar links
> are added to the ICP object when using the XICS interrupt controller.
>
> As explained in <qom/object.h>:
>
> * The caller must ensure that @target stays alive as long as
> * this property exists. In the case @target is a child of @obj,
> * this will be the case. Otherwise, the caller is responsible for
> * taking a reference.
>
> We're in the latter case for both XICS and XIVE. Add the missing
> calls to object_ref() and object_unref().
>
> This doesn't fix any known issue because the life cycle of the TCTX or
> ICP happens to be shorter than the one of the CPU or XICS fabric, but
> better safe than sorry.
>
> Signed-off-by: Greg Kurz <address@hidden>
LGTM
Reviewed-by: David Gibson <address@hidden>
> ---
> hw/intc/xics.c | 8 +++++++-
> hw/intc/xive.c | 6 +++++-
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
> index 935f325749cb..5f746079be46 100644
> --- a/hw/intc/xics.c
> +++ b/hw/intc/xics.c
> @@ -388,8 +388,10 @@ Object *icp_create(Object *cpu, const char *type,
> XICSFabric *xi, Error **errp)
> obj = object_new(type);
> object_property_add_child(cpu, type, obj, &error_abort);
> object_unref(obj);
> + object_ref(OBJECT(xi));
> object_property_add_const_link(obj, ICP_PROP_XICS, OBJECT(xi),
> &error_abort);
> + object_ref(cpu);
> object_property_add_const_link(obj, ICP_PROP_CPU, cpu, &error_abort);
> object_property_set_bool(obj, true, "realized", &local_err);
> if (local_err) {
> @@ -403,7 +405,11 @@ Object *icp_create(Object *cpu, const char *type,
> XICSFabric *xi, Error **errp)
>
> void icp_destroy(ICPState *icp)
> {
> - object_unparent(OBJECT(icp));
> + Object *obj = OBJECT(icp);
> +
> + object_unref(object_property_get_link(obj, ICP_PROP_CPU, &error_abort));
> + object_unref(object_property_get_link(obj, ICP_PROP_XICS, &error_abort));
> + object_unparent(obj);
> }
>
> /*
> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> index 38257aa02083..952a461d5329 100644
> --- a/hw/intc/xive.c
> +++ b/hw/intc/xive.c
> @@ -682,6 +682,7 @@ Object *xive_tctx_create(Object *cpu, XiveRouter *xrtr,
> Error **errp)
> obj = object_new(TYPE_XIVE_TCTX);
> object_property_add_child(cpu, TYPE_XIVE_TCTX, obj, &error_abort);
> object_unref(obj);
> + object_ref(cpu);
> object_property_add_const_link(obj, "cpu", cpu, &error_abort);
> object_property_set_bool(obj, true, "realized", &local_err);
> if (local_err) {
> @@ -698,7 +699,10 @@ error:
>
> void xive_tctx_destroy(XiveTCTX *tctx)
> {
> - object_unparent(OBJECT(tctx));
> + Object *obj = OBJECT(tctx);
> +
> + object_unref(object_property_get_link(obj, "cpu", &error_abort));
> + object_unparent(obj);
> }
>
> /*
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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