Re: [Qemu-devel] [PATCH] fix assertion in "info memory-devices" if memdev isn't accessible

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 26 Mar 2015 16:42:54 +0000
Igor Mammedov <imammedo@redhat.com> wrote:

> showing a memory device whose memdev is removed leads to an assert:
> 
> (qemu) object_add memory-backend-ram,id=ram0,size=128M
> (qemu) device_add pc-dimm,id=d0,memdev=ram0
> (qemu) object_del ram0
> (qemu) info memory-devices
> **
> ERROR:qom/object.c:1274:object_get_canonical_path_component:\
>                             assertion failed: (obj->parent != NULL)
> Aborted
> 
> so check if memdev is present before calling
> object_get_canonical_path() and in case it's not assign to
> "memdev:" field "removed" value.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>

Igor, do you want to go in through my tree?

> ---
> alternative more generic solution:
>    http://patchwork.ozlabs.org/patch/453343/
> ---
>  backends/hostmem.c       | 23 +++++++++++++++++++++++
>  hw/mem/pc-dimm.c         | 15 ++++++++++++++-
>  include/sysemu/hostmem.h |  1 +
>  qmp.c                    |  1 +
>  4 files changed, 39 insertions(+), 1 deletion(-)
> 
> diff --git a/backends/hostmem.c b/backends/hostmem.c
> index 99e8f99..aa88691 100644
> --- a/backends/hostmem.c
> +++ b/backends/hostmem.c
> @@ -227,6 +227,26 @@ static void host_memory_backend_set_prealloc(Object *obj, bool value,
>      }
>  }
>  
> +static void host_memory_backend_set_id(Object *obj, const char *id,
> +                                       Error **errp)
> +{
> +    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
> +
> +    if (backend->id) {
> +        error_set(errp, QERR_INVALID_PARAMETER_VALUE, "id",
> +                  "can't change already set value");
> +        return;
> +    }
> +    backend->id = g_strdup(id);
> +}
> +
> +static char *host_memory_backend_get_id(Object *obj, Error **errp)
> +{
> +    HostMemoryBackend *backend = MEMORY_BACKEND(obj);
> +
> +    return g_strdup(backend->id);
> +}
> +
>  static void host_memory_backend_init(Object *obj)
>  {
>      HostMemoryBackend *backend = MEMORY_BACKEND(obj);
> @@ -237,6 +257,9 @@ static void host_memory_backend_init(Object *obj)
>                                        "dump-guest-core", true);
>      backend->prealloc = mem_prealloc;
>  
> +    object_property_add_str(obj, "id",
> +                            host_memory_backend_get_id,
> +                            host_memory_backend_set_id, NULL);
>      object_property_add_bool(obj, "merge",
>                          host_memory_backend_get_merge,
>                          host_memory_backend_set_merge, NULL);
> diff --git a/hw/mem/pc-dimm.c b/hw/mem/pc-dimm.c
> index 39f0c97..482a7a0 100644
> --- a/hw/mem/pc-dimm.c
> +++ b/hw/mem/pc-dimm.c
> @@ -69,6 +69,8 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
>          DeviceState *dev = DEVICE(obj);
>  
>          if (dev->realized) {
> +            char *mdevid, *mdevpath;
> +            Object *mdev;
>              MemoryDeviceInfoList *elem = g_new0(MemoryDeviceInfoList, 1);
>              MemoryDeviceInfo *info = g_new0(MemoryDeviceInfo, 1);
>              PCDIMMDeviceInfo *di = g_new0(PCDIMMDeviceInfo, 1);
> @@ -86,7 +88,18 @@ int qmp_pc_dimm_device_list(Object *obj, void *opaque)
>              di->node = dimm->node;
>              di->size = object_property_get_int(OBJECT(dimm), PC_DIMM_SIZE_PROP,
>                                                 NULL);
> -            di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));
> +            mdevid = object_property_get_str(OBJECT(dimm->hostmem), "id",
> +                                             &error_abort);
> +            mdevpath = g_strdup_printf("/objects/%s", mdevid);
> +            g_free(mdevid);
> +            mdev = object_resolve_path_type(mdevpath, TYPE_MEMORY_BACKEND,
> +                                            NULL);
> +            if (mdev == OBJECT(dimm->hostmem)) {
> +                di->memdev = object_get_canonical_path(OBJECT(dimm->hostmem));
> +            } else {
> +                di->memdev = g_strdup("removed");
> +            }
> +            g_free(mdevpath);
>  
>              info->dimm = di;
>              elem->value = info;
> diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h
> index 1ce4394..63918aa 100644
> --- a/include/sysemu/hostmem.h
> +++ b/include/sysemu/hostmem.h
> @@ -53,6 +53,7 @@ struct HostMemoryBackend {
>      Object parent;
>  
>      /* protected */
> +    char *id;
>      uint64_t size;
>      bool merge, dump;
>      bool prealloc, force_prealloc;
> diff --git a/qmp.c b/qmp.c
> index c479e77..6f1cca7 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -649,6 +649,7 @@ void object_add(const char *type, const char *id, const QDict *qdict,
>              }
>          }
>      }
> +    object_property_set_str(obj, id, "id", NULL);
>  
>      object_property_add_child(container_get(object_get_root(), "/objects"),
>                                id, obj, &local_err);