FYI, we noticed the following commit:

commit: d3881e5015421a578bc328136471fcf1d02ac389 ("PCI: Export PCI device config accessors")
https://git.kernel.org/cgit/linux/kernel/git/helgaas/pci.git pci/enumeration

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 SandyBridge -m 512M

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


+-----------------------------------------------------------------------------------------+-----------+------------+
|                                                                                         | v4.11-rc1 | d3881e5015 |
+-----------------------------------------------------------------------------------------+-----------+------------+
| boot_successes                                                                          | 0         | 0          |
| boot_failures                                                                           | 16        | 10         |
| is_trying_to_contend_lock(ww_class_mutex)at                                             | 5         |            |
| calltrace:__ww_mutex_lock                                                               | 5         |            |
| BUG:kernel_hang_in_test_stage                                                           | 1         |            |
| invoked_oom-killer:gfp_mask=0x                                                          | 2         |            |
| Mem-Info                                                                                | 2         |            |
| Out_of_memory:Kill_process                                                              | 2         |            |
| page_allocation_failure:order:#,mode:#(GFP_HIGHUSER_MOVABLE|__GFP_ZERO),nodemask=(null) | 2         |            |
| BUG:soft_lockup-CPU##stuck_for#s                                                        | 11        |            |
| Kernel_panic-not_syncing:softlockup:hung_tasks                                          | 11        |            |
| BUG:kernel_hang_in_boot_stage                                                           | 0         | 10         |
+-----------------------------------------------------------------------------------------+-----------+------------+



[    0.000000] BRK [0x05260000, 0x05260fff] PGTABLE
[    0.000000] BRK [0x05261000, 0x05261fff] PGTABLE
[    0.000000] BRK [0x05262000, 0x05262fff] PGTABLE

Elapsed time: 510
BUG: kernel hang in boot stage

initrds=(
	/osimage/yocto/yocto-minimal-x86_64-2016-04-22.cgz
	/lkp/scheduled/vm-kbuild-yocto-x86_64-58/trinity-300s-yocto-minimal-x86_64-2016-04-22.cgz-d3881e5015421a578bc328136471fcf1d02ac389-20170331-22860-1h665bt-0.cgz
	/lkp/lkp/lkp-x86_64.cgz


To reproduce:

        git clone https://github.com/01org/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong