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Subject: Re: [PATCH resend] kernel: Make taskstats available via genetlink per namespace
Date:   Wed, 23 Feb 2022 04:56:39 +0000
Message-Id: <20220223045639.1932955-1-xu.xin16@zte.com.cn>
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>> -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.

The interface of taskstats is genetlink that is sensible in net namsespace.

> 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.

Yes. Taskstats already does convert the input process ID into the task in the
correspoding pid namsespace. Do you mean to add some check of current user's
capability like SYS_ADMIN or else?