Re: [PATCH RFC] nsproxy: strengthen the comment above copy_namespaces

[Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>]

Serge -

Is this intended for linux-cr ?
Sounds like it should go (or already?) upstream.

Oren.

On 04/30/2010 02:36 PM, Serge E. Hallyn wrote:
> copy_namespaces() cannot be used on a live task.  There are two
> reasons - it can be used to assign another task's nsproxy, which
> is not legal (for a live task).  And, it does not use
> rcu_assign_pointer, so even when we're being extra-clever it is
> unsafe.
> 
> Signed-off-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
> ---
>  kernel/nsproxy.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index f74e6c0..67d8f2b 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -115,6 +115,9 @@ out_ns:
>  /*
>   * called from clone.  This now handles copy for nsproxy and all
>   * namespaces therein.
> + * Note this should only be used in fork.  Specifically, tsk should
> + * not yet be a live task.  See the the unshare code for how to handle
> + * that.
>   */
>  int copy_namespaces(unsigned long flags, struct task_struct *tsk)
>  {