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From: Markus Armbruster <armbru@redhat.com>
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	<52976B26.1030501@suse.de>
Date: Thu, 28 Nov 2013 17:19:30 +0100
In-Reply-To: <52976B26.1030501@suse.de> ("Andreas =?utf-8?Q?F=C3=A4rber=22?=
	=?utf-8?Q?'s?= message of "Thu, 28 Nov 2013 17:11:18 +0100")
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Subject: Re: [Qemu-devel] [PATCH] qdev-monitor: device_add crashes on
	non-device driver name, fix
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To: Andreas =?utf-8?Q?F=C3=A4rber?= <afaerber@suse.de>
Cc: qemu-devel@nongnu.org, aliguori@amazon.com, qemu-stable@nongnu.org

Andreas F=C3=A4rber <afaerber@suse.de> writes:

> Am 28.11.2013 17:02, schrieb armbru@redhat.com:
>> From: Markus Armbruster <armbru@redhat.com>
>>=20
>> Watch this:
>>=20
>>     $ upstream-qemu -nodefaults -S -display none -monitor stdio
>>     QEMU 1.7.50 monitor - type 'help' for more information
>>     (qemu) device_add rng-egd
>>     /work/armbru/qemu/qdev-monitor.c:491:qdev_device_add: Object
>> 0x2089b00 is not an instance of type device
>>     Aborted (core dumped)
>>=20
>> Crashes because "rng-egd" exists, but isn't a subtype of TYPE_DEVICE.
>> Broken in commit 18b6dad.
>
> Thanks for catching this!
>
>>=20
>> Cc: qemu-stable@nongnu.org
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> ---
>>  qdev-monitor.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>=20
>> diff --git a/qdev-monitor.c b/qdev-monitor.c
>> index dc37a43..90a0cea 100644
>> --- a/qdev-monitor.c
>> +++ b/qdev-monitor.c
>> @@ -477,7 +477,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
>>          }
>>      }
>>=20=20
>> -    if (!oc) {
>> +    if (!object_class_dynamic_cast(oc, TYPE_DEVICE)) {
>
> Are you sure we don't need !oc || !object_class_dynamic_cast(oc, ...)?

Yes.  First thing object_class_dynamic_cast() does is

    if (!class) {
        return NULL;
    }

Makes sense to me.

[...]