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Date: Fri, 17 Feb 2012 12:16:10 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH] qdev: Fix qdev_try_create() semantics
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To: =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= <afaerber@suse.de>
Cc: Peter Maydell <peter.maydell@linaro.org>, Alexander Graf <agraf@suse.de>, qemu-devel Developers <qemu-devel@nongnu.org>, Igor Mammedov <imammedo@redhat.com>, Jan Kiszka <jan.kiszka@siemens.com>

On 02/16/2012 08:00 PM, Andreas Färber wrote:
> Am 17.02.2012 02:47, schrieb Andreas Färber:
>> Since QOM'ification, qdev_try_create() uses object_new() internally,
>> which asserts "type != NULL" when the type is not registered.
>> This was revealed by the combination of kvmclock's kvm_enabled() check
>> and early QOM type registration.
>>
>> Check whether the class exists before calling object_new(), so that
>> the caller (e.g., qdev_create) can fail gracefully, telling us which
>> device could not be created.
>>
>> Signed-off-by: Andreas Färber<afaerber@suse.de>
>> Cc: Anthony Liguori<aliguori@codemonkey.ws>
>
> Er, it's late here... ;)
>
> As one can guess I've managed to convert x86. Still need to cleanup but
> I pushed my work branch for the curious (and as backup!):
>
> http://repo.or.cz/w/qemu/afaerber.git/shortlog/refs/heads/qom-cpu

Applied.  Thanks.

Regards,

Anthony Liguori

>
> Andreas
>
>> ---
>>   hw/qdev.c |    3 +++
>>   1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/hw/qdev.c b/hw/qdev.c
>> index f0eb3a7..ee21d90 100644
>> --- a/hw/qdev.c
>> +++ b/hw/qdev.c
>> @@ -117,6 +117,9 @@ DeviceState *qdev_try_create(BusState *bus, const char *name)
>>   {
>>       DeviceState *dev;
>>
>> +    if (object_class_by_name(name) == NULL) {
>> +        return NULL;
>> +    }
>>       dev = DEVICE(object_new(name));
>>       if (!dev) {
>>           return NULL;
>