On 10/02/2018 08:06 PM, David Arcari wrote:

Can someone help me interpret this email?  I was expecting this to be about a
dmesg change which is expected, but the content doesn't seem to indicate that.

For the record, the commit shouldn't really introduce any functional changes.
It merely avoids calling kcalloc with count==-EINVAL.  In both cases, an error
should be returned from  acpi_pcc_probe to pcc_init, which should in turn always
return -ENODEV.

So with the commit in place, this would be logged:

[    3.957345] ACPI: [PCCT:0x00] Invalid zero length
[    3.962340] Error parsing PCC subspaces from PCCT

instead of:

[    3.957345] ACPI: [PCCT:0x00] Invalid zero length
[    3.962340] Could not allocate space for PCC mbox channels
Thanks for the explanation, robot found an new error is from this commit,
but it may not make sense.  please ignore this report.

Best Regards,
Rong Chen

On 09/29/2018 11:17 PM, kernel test robot wrote:
FYI, we noticed the following commit (built with gcc-7):

commit: afd0b1fb22269f48d68fdf269891c653818c8047 ("mailbox: PCC: handle parse error")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master

in testcase: ftq
with following parameters:

	nr_task: 100%
	samples: 6000ss
	test: cache
	freq: 20
	ucode: 0x200004d
	cpufreq_governor: performance

test-description: The FTQ benchmarks measure hardware and software interference or 'noise' on a node from the applications perspective.
test-url: https://github.com/rminnich/ftq

on test machine: 104 threads Intel(R) Xeon(R) Platinum 8170 CPU @ 2.10GHz with 192G memory

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):

2018-09-21 23:31:26 ./ftq_cache -f 20 -n 6000 -t 104 -a 360448
ticks per ns 2.09508
This ^^^ appears to be the actual error, but I don't understand what the
expected result should be or what this really means.



To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp install job.yaml  # job file is attached in this email
        bin/lkp run     job.yaml

Rong Chen

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