[libvirt] [PATCH] Fix modifying disk devices in qemu driver

[Wen Congyang]

At 05/11/2011 07:12 PM, Markus Groß Write:
> When modifying the disk devices of a live domain and the domain
> configuration, the function qemuDomainAttachDeviceConfig
> first sets dev->data->disk to NULL. Later qemuDomainAttachDeviceLive
> accesses dev->data.disk and causes a segfault.
> ---
>  src/qemu/qemu_driver.c |   14 ++++++++++----
>  1 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index b8d9c92..55e6314 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4278,12 +4278,13 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
>                           "%s", _("cannot modify device on transient domain"));
>           goto endjob;
>      }
> -    dev = virDomainDeviceDefParse(driver->caps, vm->def, xml,
> -                                  VIR_DOMAIN_XML_INACTIVE);
> -    if (dev == NULL)
> -        goto endjob;
>  
>      if (flags & VIR_DOMAIN_DEVICE_MODIFY_CONFIG) {
> +        dev = virDomainDeviceDefParse(driver->caps, vm->def, xml,
> +                                      VIR_DOMAIN_XML_INACTIVE);
> +        if (dev == NULL)
> +            goto endjob;
> +
>          /* Make a copy for updated domain. */
>          vmdef = virDomainObjCopyPersistentDef(driver->caps, vm);
>          if (!vmdef)
> @@ -4307,6 +4308,11 @@ qemuDomainModifyDeviceFlags(virDomainPtr dom, const char *xml,
>          ret = 0;
>  
>      if (!ret && (flags & VIR_DOMAIN_DEVICE_MODIFY_LIVE)) {

We should free dev before calling virDomainDeviceDefParse().

> +        dev = virDomainDeviceDefParse(driver->caps, vm->def, xml,
> +                                      VIR_DOMAIN_XML_INACTIVE);
> +        if (dev == NULL)
> +            goto endjob;
> +
>          switch (action) {
>          case QEMU_DEVICE_ATTACH:
>              ret = qemuDomainAttachDeviceLive(vm, dev, dom);