Hi Matthieu,

[CC += linux-man@]

(You forgot to CC the list.)

On 2026-05-13T10:33:38+0200, Matthieu Buffet wrote:
> Creating processes in non-direct-child PID namespaces has been possible
> since the addition of setns() support for PID namespaces in commit
> 57e8391d3276 (2012-11-19; "pidns: Add setns support"). The tree check in
> pidns_install() in kernel/pid_namespace.c has always allowed
> non-direct-child PID namespaces, but was written inline instead of the
> more readable current pidns_is_ancestor() helper (possibly explaining
> the confusion).
> 
> Fixes: 6e377abf9 (2014-09-13; "pid_namespaces.7: Parent process relationships mirror parent PID namespace relationships")
> Signed-off-by: Matthieu Buffet <matthieu@buffet.re>

Thanks!  I've applied the patch.


Cheers,
Alex

> ---
>  man/man7/pid_namespaces.7 | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/man/man7/pid_namespaces.7 b/man/man7/pid_namespaces.7
> index 1068d5be5..b19afd505 100644
> --- a/man/man7/pid_namespaces.7
> +++ b/man/man7/pid_namespaces.7
> @@ -214,11 +214,12 @@ and cannot be changed thereafter.
>  Among other things,
>  this means that
>  the parental relationship between processes
> -mirrors
> +loosely mirrors
>  the parental relationship between PID namespaces:
>  the parent of a process
>  is either in the same namespace
> -or resides in the immediate parent PID namespace.
> +or resides in an ancestor PID namespace
> +(immediate parent or not).
>  .P
>  A process may call
>  .BR unshare (2)
> 
> base-commit: 9afc5a7cfa9ecd91db055abb875e3b83d086f6b5
> -- 
> 2.47.3
> 

-- 
<https://www.alejandro-colomar.es>