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Subject: Re: hrtimers bug message on 2.6.18-rt4
From: john stultz <johnstul@us.ibm.com>
To: dwalker@mvista.com
Cc: Clark Williams <williams@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
       Ingo Molnar <mingo@elte.hu>, LKML <linux-kernel@vger.kernel.org>
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Date: Tue, 03 Oct 2006 17:38:34 -0700
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On Tue, 2006-10-03 at 17:30 -0700, Daniel Walker wrote:
> On Mon, 2006-10-02 at 10:45 -0700, john stultz wrote:
> > On Mon, 2006-10-02 at 12:39 -0500, Clark Williams wrote:
> > > I was debugging a PI mutex stress test when I got the following message
> > > on my Athlon64x2 (running 2.6.18-rt4):
> > > 
> > > BUG: time warp detected!
> > > prev > now, 101878c199393108 > 101878c081eaca2b:
> > > = 4685981405 delta, on CPU#0
> > >  [<c0104c3c>] show_trace+0x2c/0x30
> > >  [<c0104dcb>] dump_stack+0x2b/0x30
> > >  [<c012ec89>] getnstimeofday+0x249/0x270
> > 
> > Could you send me your dmesg and .config?
> > 
> 
> 
> This is likely a different issue but, I can generate this messages, like
> the following,
> 
> BUG: time warp detected!
> prev > now, 1018dd8f5e9e5c1f > 0000001748787c3e:
> = 1159920411885297633 delta, on CPU#1
>  [<c010473b>] show_trace_log_lvl+0x1eb/0x1f0
>  [<c0104efb>] show_trace+0x1b/0x20
>  [<c0105004>] dump_stack+0x24/0x30
>  [<c012b030>] do_gettimeofday+0x1a0/0x1d0
>  [<c0125024>] sys_gettimeofday+0x24/0x90
>  [<c0103567>] syscall_call+0x7/0xb
>  [<b7f9b410>] 0xb7f9b410
> 
> 
> With ltpstess . It has a settimeofday test which can trigger it. It gets
> called with wild values.

Hmmm... That sounds like a false positive, where Ingo's time warp
checking code isn't resetting on settimeofday() calls.

thanks
-john


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