[libvirt] [PATCH] qemu: avoid dereference of null pointer

[Eric Blake]

On 08/04/2011 09:51 AM, Alex Jia wrote:
> * src/qemu/qemu_driver.c: avoid dereference of null pointer.
>
> Signed-off-by: Alex Jia<ajia at redhat.com>
> ---
>   src/qemu/qemu_driver.c |   27 ++++++++++++++++++---------
>   1 files changed, 18 insertions(+), 9 deletions(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index ce19be7..28ffff7 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -5697,7 +5697,8 @@ static int qemuDomainSetBlkioParameters(virDomainPtr dom,
>                       continue;
>                   }
>
> -                persistentDef->blkio.weight = params[i].value.ui;
> +                if (params[i].value.ul)
> +                    persistentDef->blkio.weight = params[i].value.ui;

Why check ul, but then use ui?  That seems broken.

>
>               if (flags&  VIR_DOMAIN_AFFECT_CONFIG) {
> -                vmdef->cputune.quota = params[i].value.l;
> +                if (params[i].value.ul)
> +                    vmdef->cputune.quota = params[i].value.l;

Why check ul, but then use l?

Also, how does checking for a non-zero union value prevent a null 
dereference?

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org