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Date: Thu, 10 May 2012 14:09:41 -0600
From: Stephen Warren <swarren@wwwdotorg.org>
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To: Kay Sievers <kay@vrfy.org>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        William Douglas <william.douglas@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-next@vger.kernel.org
Subject: Re: Regression due to 7ff9554 "printk: convert byte-buffer to variable-length
 record buffer"
References: <4FAAB815.5040001@wwwdotorg.org> <4FAC1D09.1070004@wwwdotorg.org> <CAPXgP11UqAZgfWXUrxi7VsYr_hoDgi=cP4yn5UJ5rdPU8i5_sA@mail.gmail.com>
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On 05/10/2012 02:06 PM, Kay Sievers wrote:
> On Thu, May 10, 2012 at 9:54 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
>> On 05/09/2012 12:31 PM, Stephen Warren wrote:
>>> For me, next-20120508 prints nothing when booted, and I think also
>>> hangs. To solve this, I reverted:
>>>
>>> 7ff9554 printk: convert byte-buffer to variable-length record buffer
>>>
>>> In order to build, I also had to revert:
>>>
>>> c4e00da driver-core: extend dev_printk() to pass structured data
>>>
>>> Note: I'm running on an ARM system using a serial console, with
>>> earlyprintk enabled.
>>
>> This issue still occurs in next-20120510.
>>
>> I've tracked it down to the assignment of msg->ts_nsec near the end of
>> log_store(). If I comment this out, everything works. The problem is the
>> assignment, not the call to local_clock():
>>
>> fails:
>>        msg->ts_nsec = local_clock();
>> fails:
>>        msg->ts_nsec = 0;//local_clock();
>> works:
>>        //msg->ts_nsec = local_clock();
> 
> Weird.
> 
> What happens if you change it to:
>   cpu_clock(logbuf_cpu);
> ?
> 
> If it works, the timestamps look ok?

I doubt that would work - after all, assigning 0 fails, but not
performing the assignment at all works. But, I'll go try it...