[libvirt] [PATCH] qemu: fix the error cover issue in qemuDomainAddCgroupForThread

[John Ferlan]

On 08/14/2015 02:59 AM, Luyao Huang wrote:
> Just like commit 704cf06, the error already will be set in
> virCgroup* function, and virCgroupAddTask will return -1,
> so We will always report error "Operation not permitted"
> in this place.
> 
> Signed-off-by: Luyao Huang <lhuang at redhat.com>
> ---
>  src/qemu/qemu_driver.c | 3 ---
>  1 file changed, 3 deletions(-)
> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index fa655b5..e0d7fa5 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -4606,9 +4606,6 @@ qemuDomainAddCgroupForThread(virCgroupPtr cgroup,
>      /* Add pid/thread to the cgroup */
>      rv = virCgroupAddTask(new_cgroup, pid);
>      if (rv < 0) {
> -        virReportSystemError(-rv,
> -                             _("unable to add id %d task %d to cgroup"),
> -                             idx, pid);
>          virCgroupRemove(new_cgroup);

Apparently virCgroupRemove can also overwrite a message, see
virCgroupNewMachineSystemd for an example of how to save the error
message and restore it..

Perhaps all the callers that fail would need a similar sequence

John

I'm at KVM Forum this week so digging and finding out the answer myself
is a challenge with the flakiness of our network connection...

>          goto error;
>      }
>