Re: [PATCH v3 1/6] s390x: fix memleaks in cpu_finalize

[David Hildenbrand <david@redhat.com>]

On 27.02.20 09:58, Pan Nengyuan wrote:
> 
> 
> On 2/27/2020 4:41 PM, David Hildenbrand wrote:
>> On 27.02.20 03:50, Pan Nengyuan wrote:
>>> This patch fix memleaks when we call tests/qtest/cpu-plug-test on s390x. The leak stack is as follow:
>>>
>>> Direct leak of 48 byte(s) in 1 object(s) allocated from:
>>>     #0 0x7fb43c7cd970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970)
>>>     #1 0x7fb43be2149d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d)
>>>     #2 0x558ba96da716 in timer_new_full /mnt/sdb/qemu-new/qemu/include/qemu/timer.h:530
>>>     #3 0x558ba96da716 in timer_new /mnt/sdb/qemu-new/qemu/include/qemu/timer.h:551
>>>     #4 0x558ba96da716 in timer_new_ns /mnt/sdb/qemu-new/qemu/include/qemu/timer.h:569
>>>     #5 0x558ba96da716 in s390_cpu_initfn /mnt/sdb/qemu-new/qemu/target/s390x/cpu.c:285
>>>     #6 0x558ba9c969ab in object_init_with_type /mnt/sdb/qemu-new/qemu/qom/object.c:372
>>>     #7 0x558ba9c9eb5f in object_initialize_with_type /mnt/sdb/qemu-new/qemu/qom/object.c:516
>>>     #8 0x558ba9c9f053 in object_new_with_type /mnt/sdb/qemu-new/qemu/qom/object.c:684
>>>     #9 0x558ba967ede6 in s390x_new_cpu /mnt/sdb/qemu-new/qemu/hw/s390x/s390-virtio-ccw.c:64
>>>     #10 0x558ba99764b3 in hmp_cpu_add /mnt/sdb/qemu-new/qemu/hw/core/machine-hmp-cmds.c:57
>>>     #11 0x558ba9b1c27f in handle_hmp_command /mnt/sdb/qemu-new/qemu/monitor/hmp.c:1082
>>>     #12 0x558ba96c1b02 in qmp_human_monitor_command /mnt/sdb/qemu-new/qemu/monitor/misc.c:142
>>>
>>> Reported-by: Euler Robot <euler.robot@huawei.com>
>>> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
>>> ---
>>> Cc: Richard Henderson <rth@twiddle.net>
>>> Cc: David Hildenbrand <david@redhat.com>
>>> Cc: Cornelia Huck <cohuck@redhat.com>
>>> Cc: qemu-s390x@nongnu.org
>>> ---
>>> v2->v1:
>>> - Similarly to other cleanups, move timer_new into realize(Suggested by Philippe Mathieu-Daudé)
>>> v3->v2:
>>> - Also do the timer_free in unrealize, it seems more balance.
>>> ---
>>
>>
>> As I already said, I think this is init and not realize stuff. Do we
>> have a convention now and documented that?
>>
>> Anyhow, I don't really care
>> [...]
>>
>>
>>> @@ -453,6 +466,7 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
>>>  
>>>      device_class_set_parent_realize(dc, s390_cpu_realizefn,
>>>                                      &scc->parent_realize);
>>> +    dc->unrealize = s390_cpu_unrealizefn;
>>
>> Shouldn't we use device_class_set_parent_unrealize?
> 
> We just only declare parent_realize field in S390CPUClass(), it seems nothing to do in parent_unrealize.
> 
> typedef struct S390CPUClass {
> ...
> DeviceRealize parent_realize;    // no parent_unrealize;
> ...
> }
> 
> So I think we can't use it.

So you should add it and properly call the parent_unrealize from your
new unrealize function?

AFAIKS you are overwriting cpu_common_unrealizefn set in hw/core/cpu.c
for TYPE_CPU with this change.

-- 
Thanks,

David / dhildenb