[CRIU] [PATCH] pstree: Do not populate zero levels of task's pid

[Pavel Tikhomirov]

On 06/29/2017 02:55 PM, Kirill Tkhai wrote:
> If task's pid were hashed before the task itself
> (this may happen, when another task has sid or pgid
> equal to this pid), the pid mustn't contain zero
> levels. So, if pgid or sid has zero levels, we should
> not add them.
> 
> Otherwise, session04 --iter 3 fails with:
> 
> =[log]=> dump/zdtm/static/session04/30/2/restore.log
> ------------------------ grep Error ------------------------
> (01.858187)      6: Restoring children in our session:
> (01.858206)      6: Forking task with 303 pid (flags 0x600)
> (01.869893)      1: PID: real 145 virt 15
> (01.870247)      1: Forking task with 20 pid (flags 0x0)
> (01.872948) Error (criu/cr-restore.c:381): 0: Write -1 to sys/kernel/ns_last_pid: Invalid argument
> (01.873030) Error (criu/namespaces.c:2664): Can't set next pid
> (01.873103)      1: Error (criu/ns-common.c:46): Error answer
> (01.873123)      1: Error (criu/cr-restore.c:404): Can't request next pid
> (01.873135)      1: Error (criu/cr-restore.c:1321): Can't set next pid
> (01.873310)      1: Error (criu/cr-restore.c:1434): Can't fork for 20: No such file or directory
> 
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>

Acked-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

> ---
>   criu/pstree.c |    6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/criu/pstree.c b/criu/pstree.c
> index 9ae191292..c211c1492 100644
> --- a/criu/pstree.c
> +++ b/criu/pstree.c
> @@ -533,9 +533,9 @@ static struct pid *find_pid_or_place_in_hier(struct rb_node **root, pid_t pid, i
>   static struct pid *lookup_create_pid(pid_t *pid, int level, struct pid *pid_node, int ns_id)
>   {
>   	struct rb_node **new = NULL, *parent = NULL;
> -	int i, orig_level = level;
>   	struct pid *found;
>   	struct ns_id *ns;
> +	int i;
>   
>   	ns = lookup_ns_by_id(ns_id, &pid_ns_desc);
>   
> @@ -561,11 +561,11 @@ static struct pid *lookup_create_pid(pid_t *pid, int level, struct pid *pid_node
>   	if (!pid_node) {
>   		struct pstree_item *item;
>   
> -		item = __alloc_pstree_item(true, orig_level);
> +		item = __alloc_pstree_item(true, level);
>   		if (item == NULL)
>   			return NULL;
>   
> -		for (i = 0; i < orig_level; i++)
> +		for (i = 0; i < level; i++)
>   			item->pid->ns[i].virt = pid[i];
>   		pid_node = item->pid;
>   	}
> 

-- 
Best regards, Tikhomirov Pavel
Software Developer, Virtuozzo.