Re: [4.14] Failing selftest timer/adjtick

Miroslav Lichvar
2021-02-10T13:21:19Z

On Wed, Feb 10, 2021 at 02:07:21PM +0100, Joerg Vehlow wrote:
> On 2/10/2021 2:00 PM, Greg KH wrote:
> > Have you tried applying it to that tree to see if it solves your problem
> > and works properly? If so, please feel free to provide a working
> > backported copy, with your signed-off-by and we can consider it.
> It can be applied without any changes and fixes the problem, but since I
> have not a lot of knowledge about this subsystem, I don't know if this
> breaks anything or if it requires other patches to be applied first, to not
> break anything..
> Maybe the authors of the patch can check this easily or maybe know it.
> That's why I added them to the initial mail.

That patch cannot be applied alone. It would break the timekeeping in
not so obvious ways as there will be unexpected sources of the NTP
tracking error. IIRC, at least the following changes would need to be
included with it. There may be others.

c2cda2a5bda9 ("timekeeping/ntp: Don't align NTP frequency adjustments to ticks")
aea3706cfc4d ("timekeeping: Remove CONFIG_GENERIC_TIME_VSYSCALL_OLD")
d4d1fc61eb38 ("ia64: Update fsyscall gettime to use modern vsyscall_update")

My suggestion for a fix would be to increase the limit in the failing
test.

--
Miroslav Lichvar