[qemu-s390x] 答复: [PATCH v2] s390: avoid potential null dereference ins390_pcihost_unplug()

[Li Qiang]

What do you think of ‘g_assert_not_reached();’. For example:

 

else {

     g_assert_not_reached();

}

 

Thanks,

Li Qiang

 

 

发件人: Cornelia Huck
发送时间: 2019年1月4日 22:10
收件人: Li Qiang
抄送: address@hidden; address@hidden; address@hidden; address@hidden; address@hidden; address@hidden; address@hidden; address@hidden
主题: Re: [PATCH v2] s390: avoid potential null dereference ins390_pcihost_unplug()

 

On Thu,  3 Jan 2019 07:16:12 -0800

Li Qiang <address@hidden> wrote:

 

> When getting the 'pbdev', the if...else has no default branch.

> From Coverity, the 'pbdev' maybe null when the 'dev' is not

> the TYPE_PCI_BRIDGE/TYPE_PCI_DEVICE/TYPE_S390_PCI_DEVICE.

> This patch adds a default branch for device plug and unplug.

>

> Spotted by Coverity: CID 1398593

>

> Signed-off-by: Li Qiang <address@hidden>

> ---

> Adds a default branch for device plug per Cornelia's review.

>

>  hw/s390x/s390-pci-bus.c | 7 +++++++

>  1 file changed, 7 insertions(+)

>

> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c

> index 15759b6514..fe48a36ff6 100644

> --- a/hw/s390x/s390-pci-bus.c

> +++ b/hw/s390x/s390-pci-bus.c

> @@ -912,6 +912,9 @@ static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,

>          pbdev->fh = pbdev->idx;

>          QTAILQ_INSERT_TAIL(&s->zpci_devs, pbdev, link);

>          g_hash_table_insert(s->zpci_table, &pbdev->idx, pbdev);

> +    } else {

> +        error_setg(errp, "s390: device plug request for not supported device"

> +                   " type: %s", object_get_typename(OBJECT(dev)));

 

Maybe make this "s390/pci: plugging device type <%s> is not supported"?

 

>      }

>  }

> 

> @@ -956,6 +959,10 @@ static void s390_pcihost_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,

>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_S390_PCI_DEVICE)) {

>          pbdev = S390_PCI_DEVICE(dev);

>          pci_dev = pbdev->pdev;

> +    } else {

> +        error_setg(errp, "s390: device unplug request for not supported device"

> +                   " type: %s", object_get_typename(OBJECT(dev)));

 

Halil has a point when he suggests an assert here. If we fence the

device type in the plug function, I can't think of a way we would end

up here.

 

> +        return;

>      }

> 

>      switch (pbdev->state) {