Re: [qemu-s390x] [Qemu-devel] [PATCH v2 3/6] s390x/pci: Always delete and free the release_timer

[Collin Walling]

On 1/14/19 5:31 AM, David Hildenbrand wrote:
> We should always get rid of it. I don't see a reason to keep the timer
> alive if the devices are going away. This looks like a memory leak.
>
> (hmp) device_add virtio-mouse-pci,id=test
> (hmp) device_del test
> -> guest notified, timer pending.
> -> guest does not react for some reason (e.g. crash)
> -> s390_pcihost_timer_cb(). Timer not pending anymore. qmp_unplug().
>
> -> Device deleted. Timer expired (not pending) but not freed.
>
> Signed-off-by: David Hildenbrand <address@hidden>
> ---
>   hw/s390x/s390-pci-bus.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
> index 1775388524..59325cae3b 100644
> --- a/hw/s390x/s390-pci-bus.c
> +++ b/hw/s390x/s390-pci-bus.c
> @@ -982,7 +982,7 @@ static void s390_pcihost_unplug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>           return;
>       }
>   
> -    if (pbdev->release_timer && timer_pending(pbdev->release_timer)) {
> +    if (pbdev->release_timer) {
>           timer_del(pbdev->release_timer);
>           timer_free(pbdev->release_timer);
>           pbdev->release_timer = NULL;

Looks like the only time we would hit this is when the device is already 
in standby (i.e. not configured). So this makes sense to me.

Reviewed-by: Collin Walling <address@hidden>