linux-kernel - Re: [PATCH v4 2/3] fs/proc: apply the time namespace offset to /proc/stat btime

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Message-ID: <87eell46y2.fsf@nanos.tec.linutronix.de>
Date:   Mon, 26 Oct 2020 11:28:37 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Michael Weiß <michael.weiss@...ec.fraunhofer.de>,
        Andrei Vagin <avagin@...il.com>,
        Christian Brauner <christian.brauner@...ntu.com>
Cc:     Dmitry Safonov <0x7f454c46@...il.com>,
        linux-kernel@...r.kernel.org,
        "J . Bruce Fields" <bfields@...ldses.org>,
        Chuck Lever <chuck.lever@...cle.com>,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        Michael Weiß <michael.weiss@...ec.fraunhofer.de>
Subject: Re: [PATCH v4 2/3] fs/proc: apply the time namespace offset to /proc/stat btime

On Mon, Oct 19 2020 at 21:52, Michael Weiß wrote:

> '/proc/stat' provides the field 'btime' which states the time stamp of
> system boot in seconds. In case of time namespaces, the offset to the
> boot time stamp was not applied earlier. However, in container
> runtimes which utilize time namespaces to virtualize boottime of a
> container, this leaks information about the host system boot time.

Not sure if that qualifies as a leak. The point is that it confuses the
tasks which are in a different time universe.

Thanks,

        tglx