[CRIU] [PATCH v3 06/16] cr-restore: restore root sid before mount namespace

[Pavel Emelyanov]

On 12/10/2015 06:16 PM, Stanislav Kinsburskiy wrote:
> This is a precursor patch for AutoFS mount restore.
> To restore AutoFS indirect mount points, we have to create mount point dentries.
> This can do only the process with pgrp, configured to mount. Process, which
> does AutoFS mount call (init) at that moment is not.
> Restoring actual pgrp before sid breaks sid restoring.
> Thus, restoring of sid is required to make process group leader.
> 
> Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
> ---
>  cr-restore.c |    8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/cr-restore.c b/cr-restore.c
> index 1c0c641..8f3d28f 100644
> --- a/cr-restore.c
> +++ b/cr-restore.c
> @@ -1441,7 +1441,10 @@ static int create_children_and_session(void)
>  			return ret;
>  	}
>  
> -	restore_sid();
> +	if (getpid() == 1)

The place where you do call restore_sid() (below hunk) happens under
different check. E.g. for non-container restore you're breaking things.

> +		pr_info("Skipping restore_sid() for init\n");

Not skipping, you've already restored it, so either drop this message
or print smth like "restored earlier".

> +	else
> +		restore_sid();
>  
>  	pr_info("Restoring children in our session:\n");
>  	list_for_each_entry(child, &current->children, sibling) {
> @@ -1524,6 +1527,9 @@ static int restore_task_with_children(void *_arg)
>  		if (restore_finish_stage(CR_STATE_RESTORE_NS) < 0)
>  			goto err;
>  
> +		pr_info("Calling restore_sid() for init\n");
> +		restore_sid();
> +
>  		/*
>  		 * We need non /proc proc mount for restoring pid and mount
>  		 * namespaces and do not care for the rest of the cases.
> 
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