[libvirt] [PATCH] virBitmapFree: Change the function to a macro
Daniel P. Berrange
berrange at redhat.com
Fri Sep 6 10:36:50 UTC 2013
On Fri, Sep 06, 2013 at 10:30:56AM +0000, Liuji (Jeremy) wrote:
> The parameter of virBitmapFree function is just a pointer, not a pointer of pointer.
> The second VIR_FREE on virBitmapFree only assign NULL to the formal parameter.
> After calling the virBitmapFree function, the actual parameter are still not NULL.
> There are many code segment don't assign NULL to the formal parameter after calling
> the virBitmapFree function. This will bring potential risks.
>
> A problem scenario:
> 1) The XML of VM contain the below segment:
> <numatune>
> <memory mode='preferred' placement='auto' nodeset='0'/>
> </numatune>
> 2)virsh create the VM
> 3)In the virDomainDefParseXML funtion:
> /* Ignore 'nodeset' if 'placement' is 'auto' finally */
> if (placement_mode == VIR_NUMA_TUNE_MEM_PLACEMENT_MODE_AUTO) {
> virBitmapFree(def->numatune.memory.nodemask);
> def->numatune.memory.nodemask = NULL;
> }
> 4)Then, virsh destroy the VM. In the virDomainDefFree funtion, it also call the
> virBitmapFree function to free the nodemask:
> virBitmapFree(def->numatune.memory.nodemask);
> But after this call, the value of def->numatune.memory.nodemask is still not NULL.
> This will generate an exception.
Have you got an actual crash happening today, or is this just a theoretical
problem you're trying to address ?
Daniel
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