[CRIU] [PATCH] mount: close mnt.ns_fd only for sub-namespaces (v2)

[Pavel Emelyanov]

On 11/26/2015 05:02 PM, Andrey Vagin wrote:
> From: Andrew Vagin <avagin at virtuozzo.com>
> 
> nsid->mnt.ns_fd is initialized into 0, so currently
> fini_restore_mntns() closes the 0 descriptor if processes
> lives in a current mount namespace (NS_CRIU).
> 
> Without this patch I get the following error:
> (00.166444)   4109: Inherit fd tty:[8800:d] -> 0 has been closed
> 
> v2: typo fix
> Signed-off-by: Andrew Vagin <avagin at virtuozzo.com>
> ---
>  mount.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mount.c b/mount.c
> index 20ae79b..d0f05f6 100644
> --- a/mount.c
> +++ b/mount.c
> @@ -2653,7 +2653,7 @@ void fini_restore_mntns(void)
>  	for (nsid = ns_ids; nsid != NULL; nsid = nsid->next) {
>  		if (nsid->nd != &mnt_ns_desc)
>  			continue;
> -		if (root_item->ids->mnt_ns_id == nsid->id)
> +		if (nsid->type != NS_OTHER)
>  			continue;
>  		close(nsid->mnt.ns_fd);

Look at prepare_mnt_ns() it does this:

       for (nsid = ns_ids; nsid != NULL; nsid = nsid->next) {
                char path[PATH_MAX];

                if (nsid->nd != &mnt_ns_desc)
                        continue;
                if (root_item->ids->mnt_ns_id == nsid->id)
                        continue;

		...

		nsid->mnt.ns_fd = open_proc(PROC_SELF, "ns/mnt");
                if (nsid->mnt.ns_fd < 0)
                        goto err;

There's no single check for nsid->type, why do we have one on
the closing part?

>  	}
>