Re: [PATCH] timekeeping: Limit system time to prevent 32-bit time_t overflow

From: Arnd Bergmann
Date: Thu Oct 08 2015 - 04:52:20 EST


On Thursday 08 October 2015 08:23:44 Miroslav Lichvar wrote:
> On Wed, Oct 07, 2015 at 05:10:34PM +0200, Arnd Bergmann wrote:
> > On Wednesday 07 October 2015 16:23:44 Miroslav Lichvar wrote:
> > > Without the limit added by this patch make will go nuts just one week
> > > later when the 32-bit time_t overflows to Dec 13 1901 and the files
> > > will appear as 136 years in the future. How is that better?
> >
> > Not better or worse at all, that was my point. The time is still
> > wrong either way, whether you step back by a week or 136 years.
>
> The difference is that with the one-week step the kernel and userspace
> still agree on the current time and it is always valid from the kernel
> point of view, absolute timers can be set, etc.

Ok, I can see that as an improvement, but it still seems to give
a false sense of safety, and I feel we really should not have any code
rely on this behavior.

Arnd
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