[libvirt] new NULL-dereference in qemu_driver.c

Chris Lalancette clalance at redhat.com
Wed Apr 28 20:46:04 UTC 2010


On 04/28/2010 11:43 AM, Jim Meyering wrote:
> Chris Lalancette wrote:
>> 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.
> 
> Can any of you easily test it?
> I can't right now.

Yep, this works fine with transient domains and snapshotting.

ACK

-- 
Chris Lalancette




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