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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Michael =?utf-8?Q?Wei=C3=9F?= <michael.weiss@aisec.fraunhofer.de>,
        Andrei Vagin <avagin@gmail.com>,
        Christian Brauner <christian.brauner@ubuntu.com>
Cc:     Dmitry Safonov <0x7f454c46@gmail.com>,
        linux-kernel@vger.kernel.org,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Chuck Lever <chuck.lever@oracle.com>,
        Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Michael =?utf-8?Q?Wei=C3=9F?= <michael.weiss@aisec.fraunhofer.de>
Subject: Re: [PATCH v4 2/3] fs/proc: apply the time namespace offset to /proc/stat btime
In-Reply-To: <20201019195257.10728-3-michael.weiss@aisec.fraunhofer.de>
References: <20201019195257.10728-1-michael.weiss@aisec.fraunhofer.de> <20201019195257.10728-3-michael.weiss@aisec.fraunhofer.de>
Date:   Mon, 26 Oct 2020 11:28:37 +0100
Message-ID: <87eell46y2.fsf@nanos.tec.linutronix.de>
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On Mon, Oct 19 2020 at 21:52, Michael Wei=C3=9F 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