Re: [PATCH 02/23] x86, kaiser: do not set _PAGE_USER for init_mm page tables

From: Thomas Gleixner
Date: Thu Nov 02 2017 - 08:56:45 EST


On Thu, 2 Nov 2017, Andy Lutomirski wrote:
> > On Nov 2, 2017, at 12:33 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > Fair enough. I enabled function tracing with emulate_vsyscall as the filter
> > on a couple of machines and so far I have no hit at all. Though I found a
> > VM with a real old user space (~2005) and that actually used it.
> >
> > So for the problem at hand, I'd suggest we disable the vsyscall stuff if
> > CONFIG_KAISER=y and be done with it.
>
> I think that time() on not-so-old glibc uses it.

Sigh.

> Even more recent versions of Go use it. :(

Groan. VDSO is there since 2007 and the first usable version of Go was
released in 2012.....

Thanks,

tglx