From: Pavel Machek <pavel@denx.de>
To: Lukasz Majewski <lukma@denx.de>
Cc: Andrei Vagin <avagin@gmail.com>, Dmitry Safonov <dima@arista.com>,
Thomas Gleixner <tglx@linutronix.de>,
GNU C Library <libc-alpha@sourceware.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [Y2038][time namespaces] Question regarding CLOCK_REALTIME support plans in Linux time namespaces
Date: Sat, 14 Nov 2020 11:25:03 +0100 [thread overview]
Message-ID: <20201114102503.GB1000@bug> (raw)
In-Reply-To: <20201030110229.43f0773b@jawa>
Hi!
> I do have a question regarding the Linux time namespaces in respect of
> adding support for virtualizing the CLOCK_REALTIME.
>
> According to patch description [1] and time_namespaces documentation
> [2] the CLOCK_REALTIME is not supported (for now?) to avoid complexity
> and overhead in the kernel.
>
> Is there any plan to add support for it in a near future?
>
> Why I'm asking?
>
> It looks like this kernel feature (with CLOCK_REALTIME support
> available) would be very helpful for testing Y2038 compliance for e.g.
> glibc 32 bit ports.
>
> To be more specific - it would be possible to modify time after time_t
> 32 bit overflow (i.e. Y2038 bug) on the process running Y2038
> regression tests on the host system (64 bit one). By using Linux time
> namespaces the system time will not be affected in any way.
If big slowdown is acceptable... you can play games with ptrace. Project called "subterfugue"
should have examples how to do that.
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
prev parent reply other threads:[~2020-11-14 10:25 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-30 10:02 [Y2038][time namespaces] Question regarding CLOCK_REALTIME support plans in Linux time namespaces Lukasz Majewski
2020-10-30 13:08 ` Thomas Gleixner
2020-10-30 15:43 ` Lukasz Majewski
2020-10-30 13:58 ` Cyril Hrubis
2020-10-30 14:02 ` Zack Weinberg
2020-10-30 15:10 ` Thomas Gleixner
2020-10-30 16:58 ` Carlos O'Donell
2020-10-30 20:06 ` Thomas Gleixner
2020-10-30 22:19 ` Carlos O'Donell
2020-10-31 1:38 ` Thomas Gleixner
2020-11-03 12:43 ` Cyril Hrubis
2020-11-05 17:25 ` Carlos O'Donell
2020-11-07 0:47 ` Thomas Gleixner
2020-11-19 18:37 ` Carlos O'Donell
2020-11-20 0:14 ` Thomas Gleixner
2020-11-25 17:06 ` Petr Špaček
2020-11-25 20:37 ` Carlos O'Donell
2020-11-26 0:17 ` Thomas Gleixner
2020-11-26 3:05 ` Carlos O'Donell
2020-11-26 8:21 ` Andreas Schwab
2020-11-14 10:25 ` Pavel Machek [this message]
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