[libvirt] [PATCH 1/2] avoid vm is deleted in qemuDomainMigrateConfirm3()

[Daniel P. Berrange]

On Fri, May 20, 2011 at 03:09:09PM +0800, Wen Congyang wrote:
> If we use p2p migration and the vm is transient, vm will be deleted in
> qemuDomainMigrateConfirm3(). But the caller(doPeer2PeerMigrate() and
> qemuMigrationPerform()) still access it, and it will cause libvirtd crashed.
> 
> ---
>  src/qemu/qemu_migration.c |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index 4d7bc38..ab28416 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -1971,6 +1971,11 @@ int qemuMigrationPerform(struct qemud_driver *driver,
>          goto cleanup;
>      priv->jobActive = QEMU_JOB_MIGRATION_OUT;
>  
> +    /* Hold an extra reference because we can't allow 'vm' to be deleted in
> +     * qemuDomainMigrateConfirm3().
> +     */
> +    virDomainObjRef(vm);
> +
>      if (!virDomainObjIsActive(vm)) {
>          qemuReportError(VIR_ERR_OPERATION_INVALID,
>                          "%s", _("domain is not running"));
> @@ -2045,7 +2050,7 @@ endjob:
>          vm = NULL;
>  
>  cleanup:
> -    if (vm)
> +    if (vm && virDomainObjUnref(vm) > 0)
>          virDomainObjUnlock(vm);
>      if (event)
>          qemuDomainEventQueue(driver, event);

This is just working around a bug in qemuMigrationConfirm, which
should not have been deleting the 'vm' at all. So I am changing
that latter method to fix the issue


Daniel
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