FYI, we noticed the following commit (built with gcc-6):

commit: 8762c83c14e566226b11c68bf01ce7d5d70fee29 ("security: Kill off the sb_copy_data hook")
https://git.kernel.org/cgit/linux/kernel/git/dhowells/linux-fs.git btrfs-mount-api

in testcase: trinity
with following parameters:

	runtime: 300s

test-description: Trinity is a linux system call fuzz tester.
test-url: http://codemonkey.org.uk/projects/trinity/


on test machine: qemu-system-x86_64 -enable-kvm -cpu host -smp 2 -m 4G

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


+-------------------------------+------------+------------+
|                               | 5188a60c8b | 8762c83c14 |
+-------------------------------+------------+------------+
| boot_successes                | 10         | 0          |
| boot_failures                 | 0          | 6          |
| BUG:kernel_hang_in_test_stage | 0          | 6          |
+-------------------------------+------------+------------+



[ 2370.677861] Writes:  Total: 432288082  Max/Min: 0/0   Fail: 0 
[ 2432.120045] Writes:  Total: 443901340  Max/Min: 0/0   Fail: 0 
[ 2493.558520] Writes:  Total: 454808781  Max/Min: 0/0   Fail: 0 
[ 2555.028062] Writes:  Total: 466382884  Max/Min: 0/0   Fail: 0 
[ 2616.438626] Writes:  Total: 477022512  Max/Min: 0/0   Fail: 0 
BUG: kernel hang in test stage

Elapsed time: 2620

#!/bin/bash



To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



Thanks,
lkp