Re: Regression due to 7ff9554 "printk: convert byte-buffer tovariable-length record buffer"

From: Kay Sievers
Date: Thu May 10 2012 - 16:15:36 EST

On Thu, May 10, 2012 at 10:13 PM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote:
> On 05/10/2012 02:09 PM, Stephen Warren wrote:
>> On 05/10/2012 02:06 PM, Kay Sievers wrote:
>>> On Thu, May 10, 2012 at 9:54 PM, Stephen Warren <swarren@xxxxxxxxxxxxx> 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:
>>>> Â Â Â Âmsg->ts_nsec = local_clock();
>>>> fails:
>>>> Â Â Â Âmsg->ts_nsec = 0;//local_clock();
>>>> works:
>>>> Â Â Â Â//msg->ts_nsec = local_clock();
>>> Weird.
>>> What happens if you change it to:
>>> Â 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...
> Calling cpu_clock() instead of local_clock() fails in the same way.

Ok, didn't really see the assign to 0 you tried, sorry. :)

And 'dmesg' works when you run the box with the line commented out?

And 'cat /dev/kmsg'?

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