Re: [PATCH net] netdev-genl: report NAPI thread PID in the caller's pid namespace

[Joe Damato]

On Tue, Jun 16, 2026 at 01:17:36AM +0800, Maoyi Xie wrote:
> netdev_nl_napi_fill_one() reports the NAPI kthread PID in NETDEV_A_NAPI_PID
> using task_pid_nr(), which returns the PID in the initial pid namespace.
> 
> NETDEV_CMD_NAPI_GET does not have GENL_ADMIN_PERM and the netdev genl family
> is netnsok, so a caller in a child pid namespace can issue it. That caller
> then sees the kthread's global PID, even though the kthread is not visible
> in its pid namespace, where the value should be 0.
> 
> Translate the PID through the caller's pid namespace, the same way commit
> 3799c2570982 ("io_uring/fdinfo: translate SqThread PID through caller's
> pid_ns") did for the io_uring SQPOLL thread. The doit and dumpit paths both
> run synchronously in the caller's context, so task_active_pid_ns(current) is
> the caller's pid namespace.
> 
> Fixes: db4704f4e4df ("netdev-genl: Add PID for the NAPI thread")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Maoyi Xie <maoyixie.tju@xxxxxxxxx>
> ---
>  net/core/netdev-genl.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>

Reviewed-by: Joe Damato <joe@xxxxxxx>