[Devel] [PATCH vz10] ve: fix envID showing "/" instead of "0" for host ve0

[Vasileios Almpanis]

Reviewed-by: Vasileios Almpanis <vasileios.almpanis at virtuozzo.com>

On 5/24/26 10:32 PM, Eva Kurchatova wrote:
> ve0 is statically initialized with .ve_name = "0", but ve_online()
> unconditionally overwrites it with cgroup name, which returns "/"
> for the root cgroup.
>
> In the vz7 kernel this didn't happen because ve_create() had an early
> `goto do_init` for the root cgroup that skipped the name assignment
> entirely, preserving the static "0". The current kernel's split into
> css_alloc/css_online lost that guard.
>
> Skip ve_name assignment in ve_online() for ve0, and correspondingly
> skip kfree() on the static string in ve_offline().
>
> Signed-off-by: Eva Kurchatova <eva.kurchatova at virtuozzo.com>
>
> https://virtuozzo.atlassian.net/browse/VSTOR-131944
> Feature: ve: ve generic structures
> ---
>   kernel/ve/ve.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
> index 106fc225c60d..97442585d7bc 100644
> --- a/kernel/ve/ve.c
> +++ b/kernel/ve/ve.c
> @@ -1040,6 +1040,10 @@ static int ve_online(struct cgroup_subsys_state *css)
>   	static DEFINE_MUTEX(ve_name_mutex);
>   	struct ve_struct *ve = css_to_ve(css);
>   
> +	/* ve0 has a statically initialized ve_name; skip overwriting it */
> +	if (ve_is_super(ve))
> +		return 0;
> +
>   	mutex_lock(&ve_name_mutex);
>   	/*
>   	 * Cache ve_name to have it directly accessed. But keep in mind,
> @@ -1060,8 +1064,10 @@ static void ve_offline(struct cgroup_subsys_state *css)
>   {
>   	struct ve_struct *ve = css_to_ve(css);
>   
> -	kfree(ve->ve_name);
> -	ve->ve_name = NULL;
> +	if (!ve_is_super(ve)) {
> +		kfree(ve->ve_name);
> +		ve->ve_name = NULL;
> +	}
>   
>   	ve_cleanup_ra_data(ve, NULL);
>   }

-- 
Best regards, Vasileios Almpanis
Software Developer, Virtuozzo.