[libvirt] [PATCH] Revert "vircgroup: cleanup controllers not managed by systemd on error"

[John Ferlan]

On 9/27/18 10:13 AM, Pavel Hrdina wrote:
> This reverts commit 1602aa28f820ada66f707cef3e536e8572fbda1e.
> 
> There is no need to call virCgroupRemove() nor virCgroupFree() if
> virCgroupEnableMissingControllers() fails because it will not modify
> 'group' at all.  The cleanup is done in virCgroupMakeGroup().
> 
> Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
> ---
>  src/util/vircgroup.c | 25 ++++++++++---------------
>  1 file changed, 10 insertions(+), 15 deletions(-)
> 

For this patch,

Reviewed-by: John Ferlan <jferlan at redhat.com>

However, of course this tickle's Coverity (that's what happens when
someone makes a change in code).

Anyway, it seems calling virCgroupSetOwner with a NULL cgroup as could
happen in virLXCCgroupCreate if virCgroupNewMachine returns 0 and cgroup
== NULL, will cause a problem.

Yes, this existing and no I'm not knowledgeable (nor is Coverity for
that matter) to know if having def->idmap.uidmap is "related".

John

It's like an onion, peel one layer and we find something else.

> diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
> index f90906e4ad..548c873da8 100644
> --- a/src/util/vircgroup.c
> +++ b/src/util/vircgroup.c
> @@ -1055,7 +1055,6 @@ virCgroupNewMachineSystemd(const char *name,
>      int rv;
>      virCgroupPtr init;
>      VIR_AUTOFREE(char *) path = NULL;
> -    virErrorPtr saved = NULL;
>  
>      VIR_DEBUG("Trying to setup machine '%s' via systemd", name);
>      if ((rv = virSystemdCreateMachine(name,
> @@ -1088,24 +1087,20 @@ virCgroupNewMachineSystemd(const char *name,
>  
>      if (virCgroupEnableMissingControllers(path, pidleader,
>                                            controllers, group) < 0) {
> -        goto error;
> +        return -1;
>      }
>  
> -    if (virCgroupAddProcess(*group, pidleader) < 0)
> -        goto error;
> +    if (virCgroupAddProcess(*group, pidleader) < 0) {
> +        virErrorPtr saved = virSaveLastError();
> +        virCgroupRemove(*group);
> +        virCgroupFree(group);
> +        if (saved) {
> +            virSetError(saved);
> +            virFreeError(saved);
> +        }
> +    }
>  
>      return 0;
> -
> - error:
> -    saved = virSaveLastError();
> -    virCgroupRemove(*group);
> -    virCgroupFree(group);
> -    if (saved) {
> -        virSetError(saved);
> -        virFreeError(saved);
> -    }
> -
> -    return -1;
>  }
>  
>  
>