Re: [PATCH 23/23] clocksource tsc: add verify routine
From: Ingo Molnar
Date: Wed Jan 31 2007 - 07:46:26 EST
* Daniel Walker <dwalker@xxxxxxxxxx> wrote:
> I've included this as another user of the clocksource interface. I
> don't see a usage for this across all achitectures. So a fully generic
> version isn't needed.
well, this implementation is buggy in at least two ways:
firstly, it allows a circular verification dependency in highres+dyntick
mode between the jiffies and tsc clocksources.
secondly, verification is not done while the system is booting up:
> static void verify_tsc_freq(unsigned long unused)
> {
[...]
> + if (unlikely(system_state != SYSTEM_RUNNING))
> + goto out_timer;
so we should just go with Thomas' patch:
clocksource-add-verification-watchdog-helper.patch
which has been based on and tested on actual systems affected by these
problems.
Ingo
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