[libvirt] [PATCH 01/11] Introduce qemuDomainObjExitMonitorAlive

[Daniel P. Berrange]

On Wed, Dec 17, 2014 at 01:18:41PM +0100, Michal Privoznik wrote:
> On 16.12.2014 17:41, Ján Tomko wrote:
> >The domain might disappear during the time in monitor when
> >the virDomainObjPtr is unlocked, so the caller needs to check
> >if it's still alive.
> >
> >Introduce a helper function for the callers that want to report
> >an error in this case.
> >---
> >  src/qemu/qemu_domain.c | 17 +++++++++++++++++
> >  src/qemu/qemu_domain.h |  3 +++
> >  2 files changed, 20 insertions(+)
> >
> >diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> >index 8dd427a..d074429 100644
> >--- a/src/qemu/qemu_domain.c
> >+++ b/src/qemu/qemu_domain.c
> >@@ -1606,6 +1606,23 @@ void qemuDomainObjExitMonitor(virQEMUDriverPtr driver,
> >      qemuDomainObjExitMonitorInternal(driver, obj);
> >  }
> >
> >+/* obj must NOT be locked before calling
> >+ *
> >+ * Same as qemuDomainObjExitMonitor, but reports an error and
> >+ * returns -1 if the domain is no longer alive after exiting the monitor
> 
> Can you state explicitly that this function needs to be called whenever the
> domain object or vm->def, or privdata (any runtime info held within vm in
> general) is used after ExitMonitor()?

Are there any cases where that is not true ?  eg could we just avoid
introducing this new function, by making the existing funtion check
liveliness every time. That would avoid the class of bugs you outline
above entirely.

Regards,
Daniel
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