Re: [PATCH] namespace:unmount pid_namespace's proc_mnt when copy_net_ns failed

[ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman)]

Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> writes:

> we should call pid_ns_release_proc to unmount pid_namespace's
> proc_mnt when copy_net_ns failed in function create_new_namespaces.
>
> otherwise,the proc_mnt will not be freed and because the super_block
> of proc_mnt also add the reference of the pid_namespace,so this
> pid_namespace will never be released too.

Ouch!

Have you encountered this failure in practice or is this just from
review?

I'm trying to gauge the severity of this leak.

Eric


> Signed-off-by: Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
> ---
>  kernel/nsproxy.c |    5 ++++-
>  1 files changed, 4 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index b576f7f..d536480 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -99,8 +99,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
>  	return new_nsp;
>  
>  out_net:
> -	if (new_nsp->pid_ns)
> +	if (new_nsp->pid_ns) {
> +		if (flags & CLONE_NEWPID)
> +			pid_ns_release_proc(new_nsp->pid_ns);
>  		put_pid_ns(new_nsp->pid_ns);
> +	}
>  out_pid:
>  	if (new_nsp->ipc_ns)
>  		put_ipc_ns(new_nsp->ipc_ns);