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From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: vdso clock_gettime and time64
Date: Wed, 31 Jul 2019 18:47:55 +0200	[thread overview]
Message-ID: <20190731164754.GA22009@port70.net> (raw)
In-Reply-To: <20190731150725.GB9017@brightrain.aerifal.cx>

* Rich Felker <dalias@libc.org> [2019-07-31 11:07:25 -0400]:
> Thinking about it more, I'm actually concerned about how vdso can
> possibly work at all with checkpoint/resume functionality. The code in
> the vdso has to match the running kernel (which will update the data
> it reads), but the suspended task could be in the middle of vdso code,
> and even if not it's already bound the function entry point addresses
> and knowledge of which ones exist. We probably need the answer to this
> to know if there's even a meaningful problem to solve here. (And if
> this somehow isn't a question with a known answer already, someone's
> going to have a really bad day...)

even if the vdso is the same, criu has issues because
the time is different at restore, so there is a time
namespace proposal to address this

https://marc.info/?l=linux-api&m=156443756221829&w=2
https://www.linuxplumbersconf.org/event/2/contributions/202/attachments/25/28/LPC2018__Time_Namespace_4.pdf

if the kernel version is different then i doubt criu
can be reliable anyway.


  reply	other threads:[~2019-07-31 16:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-31  5:13 Rich Felker
2019-07-31  8:30 ` Florian Weimer
2019-07-31 15:07   ` Rich Felker
2019-07-31 16:47     ` Szabolcs Nagy [this message]
2019-08-01  9:16       ` Szabolcs Nagy
2019-07-31 17:11     ` Florian Weimer
2019-07-31 17:45       ` Rich Felker

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