Re: Regression: can't apply frequency offsets above 1000ppm.

From: John Stultz
Date: Tue Sep 01 2015 - 16:30:57 EST


On Tue, Sep 1, 2015 at 1:25 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Tue, 1 Sep 2015, Nuno GonÃalves wrote:
>
>> There is a regression on the clock system since v3.16-rc5-111-g4396e05
>> [1],
>
>> [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4396e058c52e167729729cf64ea3dfa229637086
>
> That commit has absolutely nothing to do with NTP. I fear your bisect
> went down the wrong road somewhere.
>
>> where the clock doesn't apply frequency offsets above about
>> 1000ppm [2].
>
> This looks pretty familiar.
>
> The issue was introduced with commit 5e5aeb4367b (time: adjtimex:
> Validate the ADJ_FREQUENCY values). That patch was tagged for stable,
> so it got backported.
>
> The fix is in commit 29183a70b0b82 (ntp: Fixup adjtimex freq
> validation on 32-bit systems). That commit was tagged for stable as
> well, but with the extra '#3.19+' limitation.
>
> So in the worst case 5e5aeb4367b hit a stable tree < 3.19, but
> 29183a70b0b82 did not.

Hrm. So that would be problematic, and I'll have to follow up that
both changes got backported together.

But I don't think that's the issue here, since the problem supposedly
continues w/ 4.2...

thanks
-john
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