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

[Peter Maydell]

On Sat, 15 Feb 2020 at 15:48, Philippe Mathieu-Daudé <address@hidden> 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.

thanks
-- PMM