[libvirt] [PATCHv2 06/14] qemu: Implement request of vCPU state using the guest agent

[Daniel P. Berrange]

On Wed, Jun 05, 2013 at 03:43:57PM +0200, Peter Krempa wrote:
> This patch implements the VIR_DOMAIN_VCPU_AGENT flag for the
> qemuDomainGetVcpusFlags() libvirt API implementation.
> ---
>  src/qemu/qemu_driver.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 56 insertions(+), 4 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 3db21d4..2922fce 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4406,17 +4406,24 @@ static int
>  qemuDomainGetVcpusFlags(virDomainPtr dom, unsigned int flags)
>  {
>      virQEMUDriverPtr driver = dom->conn->privateData;
> +    qemuDomainObjPrivatePtr priv;
>      virDomainObjPtr vm;
>      virDomainDefPtr def;
>      int ret = -1;
>      virCapsPtr caps = NULL;
> +    qemuAgentCPUInfoPtr cpuinfo = NULL;
> +    int ncpuinfo;

This is not initialized here
 
> +
> +        if (!virDomainObjIsActive(vm)) {
> +            virReportError(VIR_ERR_OPERATION_INVALID, "%s",
> +                           _("domain is not running"));
> +            goto endjob;
> +        }

This 'goto' jumps over the only initialization of 'ncpuinfo':

> +
> +        qemuDomainObjEnterAgent(vm);
> +        ncpuinfo = qemuAgentGetVCPUs(priv->agent, &cpuinfo);
> +        qemuDomainObjExitAgent(vm);
> +

> +endjob:
> +        if (qemuDomainObjEndJob(driver, vm) == 0)
> +            vm = NULL;
> +
> +        if (ncpuinfo < 0)
> +            goto cleanup;

So here you're accessing uninitialized memory.


  CC       libvirt_driver_qemu_impl_la-qemu_driver.lo
qemu/qemu_driver.c: In function 'qemuDomainGetVcpusFlags':
qemu/qemu_driver.c:4573:9: error: 'ncpuinfo' may be used uninitialized in this function [-Werror=maybe-uninitialized]
qemu/qemu_driver.c: At top level:


Daniel
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