[libvirt] [PATCH v2 5/6] qemu: Resolve Coverity FORWARD_NULL

[Peter Krempa]

On Fri, Sep 25, 2015 at 12:31:44 -0400, John Ferlan wrote:
> Coverity notices that net->ifname is potentially referenced after a
> VIR_FREE().  Looking through history, the vport check code was added by
> commit id 'df8100463' and later augmented by commit id 'd490f47b'. The
> data is allocated via virNetDevMacVLanCreateWithVPortProfile, so it is
> reasonable that it's free'd after the virNetDevMacVLanDeleteWithVPortProfile
> call. Additionally, the virNetDevTapDelete call was added by commit id
> '075650ff4', but it doesn't seem there's a corresponding VIR_FREE of
> the ifname, so include that as well while we're at it.
> 
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
>  src/qemu/qemu_process.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index f2586a1..e3d1c62 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -5321,6 +5321,7 @@ void qemuProcessStop(virQEMUDriverPtr driver,

Since we are in qemuProcessStop, which means that the whole active
definition will be nuked a few lines below this code ...

>  
>      def = vm->def;
>      for (i = 0; i < def->nnets; i++) {
> +        bool free_net_iface = false;
>          virDomainNetDefPtr net = def->nets[i];
>          vport = virDomainNetGetActualVirtPortProfile(net);
>  
> @@ -5332,13 +5333,16 @@ void qemuProcessStop(virQEMUDriverPtr driver,
>                               virDomainNetGetActualDirectMode(net),
>                               virDomainNetGetActualVirtPortProfile(net),
>                               cfg->stateDir));
> -            VIR_FREE(net->ifname);
> +            free_net_iface = true;

.. should we even bother to do this? Just remove the free and let
virDomainDefFree remove it afterwards either when vm->def is being
replaced by vm->newDef or when the transient vm object is being nuked
too.

Peter
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