Re: [PATCH 2/2] hw/sd/sd: Delay timer_new_ns() from init to realize to avoid memleaks

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 2/17/20 2:26 PM, Peter Maydell wrote:
> On Sat, 15 Feb 2020 at 15:48, Philippe Mathieu-Daudé <philmd@redhat.com> wrote:
>>
>> In commit f3a508eb4e the Euler Robot reported calling timer_new()
>> in instance_init() can leak heap memory. The easier fix is to
>> delay the timer creation at instance realize(). Similarly move
>> timer_del() into a new instance unrealize() method.
> 
>> diff --git a/hw/sd/sd.c b/hw/sd/sd.c
>> index 71a9af09ab..d72cf3de2a 100644
>> --- a/hw/sd/sd.c
>> +++ b/hw/sd/sd.c
>> @@ -2058,14 +2058,12 @@ static void sd_instance_init(Object *obj)
>>      SDState *sd = SD_CARD(obj);
>>
>>      sd->enable = true;
>> -    sd->ocr_power_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, sd_ocr_powerup, sd);
>>  }
>>
>>  static void sd_instance_finalize(Object *obj)
>>  {
>>      SDState *sd = SD_CARD(obj);
>>
>> -    timer_del(sd->ocr_power_timer);
>>      timer_free(sd->ocr_power_timer);
>>  }
>>
>> @@ -2098,6 +2096,15 @@ static void sd_realize(DeviceState *dev, Error **errp)
>>          }
>>          blk_set_dev_ops(sd->blk, &sd_block_ops, sd);
>>      }
>> +
>> +    sd->ocr_power_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, sd_ocr_powerup, sd);
>> +}
>> +
>> +static void sd_unrealize(DeviceState *dev, Error **errp)
>> +{
>> +    SDState *sd = SD_CARD(dev);
>> +
>> +    timer_del(sd->ocr_power_timer);
>>  }
> 
> Here too the old code was doing things correctly in that
> it does a timer_del/timer_free on the timer it allocates
> in instance_init, and the new code has weirdly split the
> freeing between unrealize and finalize.

Indeed I now see it, thanks.

> 
> thanks
> -- PMM
>