FYI, we noticed the following commit:

commit: 1442488925f53e8f8ffc3c142e133e7ec287173f ("block: fix lifetime of request_queue / backing_dev_info relative to bdev")
url: https://github.com/0day-ci/linux/commits/Dan-Williams/block-fix-backing_dev_info-lifetime/20170108-114310


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-i386 -enable-kvm -smp 2 -m 320M

caused below changes:


+------------------------------------------------------------------+------------+------------+
|                                                                  | 4cf184638b | 1442488925 |
+------------------------------------------------------------------+------------+------------+
| boot_successes                                                   | 0          | 0          |
| boot_failures                                                    | 2          | 17         |
| kernel_BUG_at_lib/list_debug.c                                   | 2          | 1          |
| invalid_opcode:#[##]PREEMPT_DEBUG_PAGEALLOC                      | 2          | 1          |
| Kernel_panic-not_syncing:Fatal_exception                         | 2          | 1          |
| WARNING:at_mm/backing-dev.c:#bdi_exit                            | 0          | 15         |
| WARNING:at_include/linux/kref.h:#kobject_get                     | 0          | 16         |
| INFO:rcu_preempt_detected_stalls_on_CPUs/tasks                   | 0          | 5          |
| BUG:kernel_hang_in_test_stage                                    | 0          | 5          |
| invoked_oom-killer:gfp_mask=0x                                   | 0          | 1          |
| Mem-Info                                                         | 0          | 1          |
| page_allocation_failure:order:#,mode:#(GFP_KERNEL|__GFP_NORETRY) | 0          | 1          |
| WARNING:at_lib/kobject.c:#kobject_put                            | 0          | 1          |
+------------------------------------------------------------------+------------+------------+



[   88.027646]     ide0: BM-DMA at 0xc080-0xc087
[   88.027911]     ide1: BM-DMA at 0xc088-0xc08f
[   88.027975] Probing IDE interface ide0...
[   88.238393] WARNING: CPU: 0 PID: 17 at mm/backing-dev.c:876 bdi_exit+0x33/0x65
[   88.257859] CPU: 0 PID: 17 Comm: kworker/0:1 Not tainted 4.10.0-rc2-00104-g1442488 #1
[   88.268429] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014
[   88.281879] Workqueue: events bdev_release
[   88.287673] Call Trace:
[   88.291074]  dump_stack+0x16/0x18
[   88.295550]  __warn+0xaa/0xc1
[   88.299735]  ? bdi_exit+0x33/0x65


To reproduce:

        git clone git://git.kernel.org/pub/scm/linux/kernel/git/wfg/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script  # job-script is attached in this email



Thanks,
Xiaolong