xu xin <cgel.zte@xxxxxxxxx> writes:
> Currently, the application getdelays cannot get taskstats in a net
> namespace. The returned error is just like the following:
> -sh-4.4# ps -ef | tail -5
> root 186 2 0 09:23 ? 00:00:00 [kworker/2:1H]
> root 187 2 0 09:23 ? 00:00:00 [kworker/0:2-eve]
> root 190 183 0 09:23 ? 00:00:00 -sh
> root 198 190 0 09:25 ? 00:00:00 ps -ef
> root 199 190 0 09:25 ? 00:00:00 tail -5
> -sh-4.4#
> -sh-4.4# ./getdelays -d -p 186 -v
> print delayacct stats ON
> debug on
> Error getting family id, errno 0
>
> As more and more applications are deployed in containers like Docker,
> it is necessary to support getdelays to be used in net namespace.
> Taskstats is safe for use per namespace as genetlink checks the
> capability of namespace message by netlink_ns_capable().
>
> Make taskstats available via genetlink per namespace.
Let me add a polite nack to this patch.
Taskstats is completely senseless in a network namespace. There is no
translation of identifiers into the context of the receiver of the
message.
As such taskstats can not be meaningfully used in a container.
To make this work requires updating the taskstats code to do something
sensible when in a pid namespace, as well as when in a network
namespace.
I would like to give a suggest on how to do something sensible but
I don't have any idea at this point. The code would have been converted
long ago on general principles if this was a straight forward thing to
do.
The taskstats interface only makes sense when you are within all of the
initial namespaces.
Eric
> Reported-by: Changcheng Deng <deng.changcheng@xxxxxxxxxx>
> Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
> ---
> kernel/taskstats.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/kernel/taskstats.c b/kernel/taskstats.c
> index 2b4898b4752e..4d6bcaaf52a0 100644
> --- a/kernel/taskstats.c
> +++ b/kernel/taskstats.c
> @@ -664,6 +664,7 @@ static struct genl_family family __ro_after_init = {
> .module = THIS_MODULE,
> .ops = taskstats_ops,
> .n_ops = ARRAY_SIZE(taskstats_ops),
> + .netnsok = true,
> };
>
> /* Needed early in initialization */
