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

Eric W. Biederman
2012-11-02T07:03:08Z

> 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@cn.fujitsu.com>
> ---
> 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);