Re: [libvirt] [PATCH 1/2] Fix multiple potential NULL pointer references in monitor usage

On 05/17/2010 05:53 AM, Daniel P. Berrange wrote: > @@ -5444,15 +5471,15 @@ static int qemudDomainHotplugVcpus(virDomainObjPtr vm, unsigned int nvcpus) > int i, rc; > int ret = -1; > > + qemuDomainObjEnterMonitor(vm); > + > /* We need different branches here, because we want to offline > * in reverse order to onlining, so any partial fail leaves us in a > * reasonably sensible state */ > if (nvcpus > vm->def->vcpus) { > for (i = vm->def->vcpus ; i < nvcpus ; i++) { > /* Online new CPU */ > - qemuDomainObjEnterMonitor(vm); > rc = qemuMonitorSetCPU(priv->mon, i, 1); > - qemuDomainObjExitMonitor(vm); > if (rc == 0) > goto unsupported; > if (rc < 0) > @@ -5463,9 +5490,7 @@ static int qemudDomainHotplugVcpus(virDomainObjPtr vm, unsigned int nvcpus) > } else { > for (i = vm->def->vcpus - 1 ; i >= nvcpus ; i--) { > /* Offline old CPU */ > - qemuDomainObjEnterMonitor(vm); > rc = qemuMonitorSetCPU(priv->mon, i, 0); > - qemuDomainObjExitMonitor(vm); > if (rc == 0) > goto unsupported; > if (rc < 0) > @@ -5478,6 +5503,7 @@ static int qemudDomainHotplugVcpus(virDomainObjPtr vm, unsigned int nvcpus) > ret = 0; > > cleanup: > + qemuDomainObjExitMonitor(vm); This is a larger critical section now, but it didn't look like you were doing anything that had potentially long-running actions that would block such a large critical section.