A TYPE_SCLP_CPU_HOTPLUG device for handling cpu hotplug events
is already created by the sclp event facility. Adding a second
TYPE_SCLP_CPU_HOTPLUG device via -device sclp-cpu-hotplug creates
an ambiguity in raise_irq_cpu_hotplug(), leading to a crash once
a cpu is hotplugged.

To fix this, disallow creating a sclp-cpu-hotplug device manually.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
---
 hw/s390x/sclpcpu.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/s390x/sclpcpu.c b/hw/s390x/sclpcpu.c
index 023d059a46..3ee890b392 100644
--- a/hw/s390x/sclpcpu.c
+++ b/hw/s390x/sclpcpu.c
@@ -82,6 +82,12 @@ static void cpu_class_init(ObjectClass *oc, void *data)
     k->get_receive_mask = receive_mask;
     k->read_event_data = read_event_data;
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+    /*
+     * Reason: raise_irq_cpu_hotplug() depends on an unique
+     * TYPE_SCLP_CPU_HOTPLUG device, which is already created
+     * by the sclp event facility
+     */
+    dc->user_creatable = false;
 }
 
 static const TypeInfo sclp_cpu_info = {
-- 
2.13.6

On 04.10.2017 17:46, Cornelia Huck wrote:
> A TYPE_SCLP_CPU_HOTPLUG device for handling cpu hotplug events
> is already created by the sclp event facility. Adding a second
> TYPE_SCLP_CPU_HOTPLUG device via -device sclp-cpu-hotplug creates
> an ambiguity in raise_irq_cpu_hotplug(), leading to a crash once
> a cpu is hotplugged.
> 
> To fix this, disallow creating a sclp-cpu-hotplug device manually.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
>  hw/s390x/sclpcpu.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/s390x/sclpcpu.c b/hw/s390x/sclpcpu.c
> index 023d059a46..3ee890b392 100644
> --- a/hw/s390x/sclpcpu.c
> +++ b/hw/s390x/sclpcpu.c
> @@ -82,6 +82,12 @@ static void cpu_class_init(ObjectClass *oc, void *data)
>      k->get_receive_mask = receive_mask;
>      k->read_event_data = read_event_data;
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    /*
> +     * Reason: raise_irq_cpu_hotplug() depends on an unique
> +     * TYPE_SCLP_CPU_HOTPLUG device, which is already created
> +     * by the sclp event facility
> +     */
> +    dc->user_creatable = false;
>  }

Reviewed-by: Thomas Huth <thuth@redhat.com>

On 10/04/2017 05:46 PM, Cornelia Huck wrote:
> A TYPE_SCLP_CPU_HOTPLUG device for handling cpu hotplug events
> is already created by the sclp event facility. Adding a second
> TYPE_SCLP_CPU_HOTPLUG device via -device sclp-cpu-hotplug creates
> an ambiguity in raise_irq_cpu_hotplug(), leading to a crash once
> a cpu is hotplugged.
> 
> To fix this, disallow creating a sclp-cpu-hotplug device manually.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>

Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>

Most of these missing user_create things stem from a time of qdev.no_user
which was then later deprecated and replaced with cannot_instantiate_with_device_add_yet
It was supposed to be a temporary measure but now we all know that there ARE devices
which are not user_creatable.
    
So its good to get this all fixed.

> ---
>  hw/s390x/sclpcpu.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/s390x/sclpcpu.c b/hw/s390x/sclpcpu.c
> index 023d059a46..3ee890b392 100644
> --- a/hw/s390x/sclpcpu.c
> +++ b/hw/s390x/sclpcpu.c
> @@ -82,6 +82,12 @@ static void cpu_class_init(ObjectClass *oc, void *data)
>      k->get_receive_mask = receive_mask;
>      k->read_event_data = read_event_data;
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
> +    /*
> +     * Reason: raise_irq_cpu_hotplug() depends on an unique
> +     * TYPE_SCLP_CPU_HOTPLUG device, which is already created
> +     * by the sclp event facility
> +     */
> +    dc->user_creatable = false;
>  }
> 
>  static const TypeInfo sclp_cpu_info = {
> 

On Wed,  4 Oct 2017 17:46:47 +0200
Cornelia Huck <cohuck@redhat.com> wrote:

> A TYPE_SCLP_CPU_HOTPLUG device for handling cpu hotplug events
> is already created by the sclp event facility. Adding a second
> TYPE_SCLP_CPU_HOTPLUG device via -device sclp-cpu-hotplug creates
> an ambiguity in raise_irq_cpu_hotplug(), leading to a crash once
> a cpu is hotplugged.
> 
> To fix this, disallow creating a sclp-cpu-hotplug device manually.
> 
> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> ---
>  hw/s390x/sclpcpu.c | 6 ++++++
>  1 file changed, 6 insertions(+)

Queued to s390-next.