Re: [PATCH] pl031: add finalize function to avoid memleaks

[Pan Nengyuan]

On 2/3/2020 5:58 PM, Peter Maydell wrote:
> On Mon, 3 Feb 2020 at 07:47, <address@hidden> wrote:
>>
>> From: Pan Nengyuan <address@hidden>
>>
>> There is a memory leak when we call 'device_list_properties' with
>> typename = pl031. It's easy to reproduce as follow:
>>
>>   virsh qemu-monitor-command vm1 --pretty '{"execute": 
>> "device-list-properties", "arguments": {"typename": "pl031"}}'
>>
>> The memory leak stack:
>>   Direct leak of 48 byte(s) in 1 object(s) allocated from:
>>     #0 0x7f6e0925a970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970)
>>     #1 0x7f6e06f4d49d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d)
>>     #2 0x564a0f7654ea in timer_new_full 
>> /mnt/sdb/qemu/include/qemu/timer.h:530
>>     #3 0x564a0f76555d in timer_new /mnt/sdb/qemu/include/qemu/timer.h:551
>>     #4 0x564a0f765589 in timer_new_ns /mnt/sdb/qemu/include/qemu/timer.h:569
>>     #5 0x564a0f76747d in pl031_init /mnt/sdb/qemu/hw/rtc/pl031.c:198
>>     #6 0x564a0fd4a19d in object_init_with_type /mnt/sdb/qemu/qom/object.c:360
>>     #7 0x564a0fd4b166 in object_initialize_with_type 
>> /mnt/sdb/qemu/qom/object.c:467
>>     #8 0x564a0fd4c8e6 in object_new_with_type /mnt/sdb/qemu/qom/object.c:636
>>     #9 0x564a0fd4c98e in object_new /mnt/sdb/qemu/qom/object.c:646
>>     #10 0x564a0fc69d43 in qmp_device_list_properties 
>> /mnt/sdb/qemu/qom/qom-qmp-cmds.c:204
>>     #11 0x564a0ef18e64 in qdev_device_help /mnt/sdb/qemu/qdev-monitor.c:278
>>
>> Reported-by: Euler Robot <address@hidden>
>> Signed-off-by: Pan Nengyuan <address@hidden>
>> ---
>>  hw/rtc/pl031.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/hw/rtc/pl031.c b/hw/rtc/pl031.c
>> index ae47f09635..50664ca000 100644
>> --- a/hw/rtc/pl031.c
>> +++ b/hw/rtc/pl031.c
>> @@ -194,6 +194,15 @@ static void pl031_init(Object *obj)
>>      s->timer = timer_new_ns(rtc_clock, pl031_interrupt, s);
>>  }
>>
>> +static void pl031_finalize(Object *obj)
>> +{
>> +    PL031State *s = PL031(obj);
>> +    if (s->timer) {
>> +        timer_del(s->timer);
>> +        timer_free(s->timer);
>> +    }
>> +}
>> +
>>  static int pl031_pre_save(void *opaque)
>>  {
>>      PL031State *s = opaque;
>> @@ -329,6 +338,7 @@ static const TypeInfo pl031_info = {
>>      .parent        = TYPE_SYS_BUS_DEVICE,
>>      .instance_size = sizeof(PL031State),
>>      .instance_init = pl031_init,
>> +    .instance_finalize = pl031_finalize,
>>      .class_init    = pl031_class_init,
>>  };
> 
> The more usual way to fix this I think is to delay
> the timer_new until realize rather than putting it
> into instance_init, since the pl031 can't be
> hotplugged.

Hmm, you are right, I will change it in next version.

Thanks.

> 
> thanks
> -- PMM
> .
>