Messages in this thread | | | Date | Mon, 19 Mar 2001 07:33:56 +0000 | From | Russell King <> | Subject | Re: gettimeofday question |
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On Sat, Mar 03, 2001 at 12:49:04PM +0000, Russell King wrote: > Hi, > > I've noticed that one of my machines here suffers from the "time going > backwards problem" and so started thinking about the x86 solution. > > I've come to the conclusion that it has a hole which could cause it > to return the wrong time in one specific case: > > - in do_gettimeofday(), we disable irqs (read_lock_irqsave) > - the ISA timer wraps, but we've got interrupts disabled, so no update > of xtime or jiffies occurs > - in do_slow_gettimeoffset(), we read the timer, which has wrapped > - since jiffies_p != jiffies, we do not apply any correction > - our idea of time is now one jiffy slow.
I never heard any response to this. Could some knowledgeable person please take a look at it?
Thanks.
-- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html
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