Re: [PATCH 08/20 -v5] initialize the clock source to jiffies clock.

[Tim Bird <tim.bird@am.sony.com>]

Steven Rostedt wrote:
> The latency tracer can call clocksource_read very early in bootup and
> before the clock source variable has been initialized. This results in a
> crash at boot up (even before earlyprintk is initialized). Since the
> clock->read variable points to NULL.
> 
> This patch simply initializes the clock to use clocksource_jiffies, so
> that any early user of clocksource_read will not crash.

There's a similar problem with reads of sched_clock() too early
on some architectures.  This problem reminds me of a fix I need
to re-send to the ARM mailing list.  That aside, I heartily recommend
applying this patch, whether the rest of this system gets mainlined
or not.

FWIW:
Acked-by: Tim Bird <tim.bird@am.sony.com>

 -- Tim


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Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Corporation of America
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