FYI, we noticed the following commit (built with gcc-8):

commit: a0c863ed7008cebd17d8ed37e55c7252f5b0852d ("[PATCH] drivers: base: add support to skip power management in device/driver model")
url: https://github.com/0day-ci/linux/commits/Sudeep-Holla/drivers-base-add-support-to-skip-power-management-in-device-driver-model/20190207-234715
base: https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git linux-next

in testcase: locktorture
with following parameters:

	runtime: 300s
	test: cpuhotplug

test-description: This torture test consists of creating a number of kernel threads which acquire the lock and hold it for specific amount of time, thus simulating different critical region behaviors.
test-url: https://www.kernel.org/doc/Documentation/locking/locktorture.txt


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

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


+-------------------------------------------------------+------------+------------+
|                                                       | b1e72d3070 | a0c863ed70 |
+-------------------------------------------------------+------------+------------+
| boot_successes                                        | 16         | 4          |
| boot_failures                                         | 1          | 14         |
| BUG:kernel_in_stage                                   | 1          | 2          |
| WARNING:at_fs/sysfs/group.c:#sysfs_remove_group       | 0          | 11         |
| RIP:sysfs_remove_group                                | 0          | 11         |
| BUG:kernel_reboot-without-warning_in_early-boot_stage | 0          | 1          |
+-------------------------------------------------------+------------+------------+



[   40.550911] WARNING: CPU: 0 PID: 12 at fs/sysfs/group.c:256 sysfs_remove_group+0x41/0x76
[   40.553757] Modules linked in: locktorture torture
[   40.555375] CPU: 0 PID: 12 Comm: cpuhp/0 Not tainted 5.0.0-rc5-00062-ga0c863e #1
[   40.558078] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[   40.560978] RIP: 0010:sysfs_remove_group+0x41/0x76
[   40.562595] Code: 30 49 89 fc 31 d2 48 89 df e8 a7 c9 ff ff 48 89 c3 48 85 c0 75 23 49 8b 14 24 48 8b 75 00 48 c7 c7 16 a4 28 82 e8 3c aa df ff <0f> 0b 5b 5d 41 5c c3 48 89 df e8 98 c4 ff ff 48 89 ee 48 89 df e8
[   40.568050] RSP: 0018:ffffc90000383db0 EFLAGS: 00010282
[   40.569756] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000007
[   40.571810] RDX: 0000000000000000 RSI: ffff88807a015700 RDI: ffff88807a015700
[   40.573866] RBP: ffffffff820cf760 R08: 0000000080000001 R09: ffff8880000bd960
[   40.575915] R10: ffffea00015e8f00 R11: ffffc90000383c4f R12: ffff88806a94d010
[   40.577968] R13: 000000000001ef60 R14: ffffffff81631af9 R15: 0000000000000000
[   40.580021] FS:  0000000000000000(0000) GS:ffff88807a000000(0000) knlGS:0000000000000000
[   40.582861] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   40.584674] CR2: 00000000004215e0 CR3: 000000007e5f6000 CR4: 00000000000406f0
[   40.586731] Call Trace:
[   40.587946]  device_del+0x54/0x2b6
[   40.589313]  device_unregister+0x41/0x4a
[   40.590764]  cpu_cache_sysfs_exit+0x5a/0xa7
[   40.592267]  ? smpboot_thread_fn+0x1a/0x1cd
[   40.593763]  cacheinfo_cpu_pre_down+0x1d/0x28
[   40.595301]  cpuhp_invoke_callback+0x117/0x516
[   40.596846]  ? __schedule+0x6af/0x714
[   40.598260]  ? smpboot_thread_fn+0x1a/0x1cd
[   40.599759]  ? sort_range+0x1c/0x1c
[   40.601137]  cpuhp_thread_fun+0xd5/0x10f
[   40.602590]  ? sort_range+0x1c/0x1c
[   40.603955]  smpboot_thread_fn+0x1b6/0x1cd
[   40.605446]  kthread+0x120/0x128
[   40.606765]  ? kthread_park+0x76/0x76
[   40.608177]  ret_from_fork+0x3a/0x50
[   40.624071] ---[ end trace 69e3d9d5b6e4ca2d ]---


To reproduce:

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        find lib/ | cpio -o -H newc --quiet | gzip > modules.cgz
	bin/lkp qemu -k <bzImage> -m modules.cgz job-script # job-script is attached in this email




Thanks,
Rong Chen