FYI, we noticed the following commit (built with gcc-7):

commit: b885537f7e920dd4e72e6170cf39f7117465d3f9 ("tpm: call tpm2_flush_space() on error in tpm_try_transmit()")
git://git.infradead.org/users/jjs/linux-tpmdd nested

in testcase: ftq
with following parameters:

	nr_task: 100%
	samples: 6000ss
	test: cache
	freq: 20
	ucode: 0xb00002e
	cpufreq_governor: powersave

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: 192 threads Intel(R) Xeon(R) CPU E7-8890 v4 @ 2.20GHz with 512G memory

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




2018-11-30 23:04:39 ./ftq_cache -f 20 -n 6000 -t 192 -a 327680
ticks per ns 2.19471



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



Thanks,
Rong Chen