[libvirt] new NULL-dereference in qemu_driver.c

[Chris Lalancette]

On 04/27/2010 04:40 PM, Jim Meyering wrote:
> Daniel P. Berrange wrote:
> 
>> On Tue, Apr 27, 2010 at 06:45:16PM +0200, Jim Meyering wrote:
>>> I ran clang on the very latest and it spotted this problem:
>>> >From qemu_driver.c, around line 11100,
>>>
>>>     else {
>>>         /* qemu is a little funny with running guests and the restoration
>>>          * of snapshots.  If the snapshot was taken online,
>>>          * then after a "loadvm" monitor command, the VM is set running
>>>          * again.  If the snapshot was taken offline, then after a "loadvm"
>>>          * monitor command the VM is left paused.  Unpausing it leads to
>>>          * the memory state *before* the loadvm with the disk *after* the
>>>          * loadvm, which obviously is bound to corrupt something.
>>>          * Therefore we destroy the domain and set it to "off" in this case.
>>>          */
>>>
>>>         if (virDomainObjIsActive(vm)) {
>>>             qemudShutdownVMDaemon(driver, vm);
>>>             event = virDomainEventNewFromObj(vm,
>>>                                              VIR_DOMAIN_EVENT_STOPPED,
>>>                                              VIR_DOMAIN_EVENT_STOPPED_FROM_SNAPSHOT);
>>>             if (!vm->persistent) {
>>>                 if (qemuDomainObjEndJob(vm) > 0)
>>>                     virDomainRemoveInactive(&driver->domains, vm);
>>>                 vm = NULL;
>>
>> This needs to add 'goto endjob' or possibly 'goto cleanup'
> 
> No point in endjob, since it does nothing when vm == NULL.
> 
> Here's a tentative patch for that and another, similar problem
> (haven't even compiled it or run it through clang, but have to run).
> Will follow up tomorrow.

Yeah, this looks reasonable and is what I was going to submit.  It
would be good to give a test first, though.

-- 
Chris Lalancette