Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 6a1b34c0a339fdc75d7932ad5702f2177c9d7a1c ("drm/fb-helper: Move damage blit code and its setup into separate routine")
url: https://github.com/0day-ci/linux/commits/Thomas-Zimmermann/drm-fb-helper-Various-fixes-and-cleanups/20201120-182750


in testcase: trinity
version: trinity-static-i386-x86_64-f93256fb_2019-08-28
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 -cpu SandyBridge -smp 2 -m 8G

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


+-----------------------------------------------------------------------+------------+------------+
|                                                                       | 154f2d1afd | 6a1b34c0a3 |
+-----------------------------------------------------------------------+------------+------------+
| WARNING:at_drivers/gpu/drm/drm_fb_helper.c:#drm_fb_helper_damage_work | 0          | 36         |
| EIP:drm_fb_helper_damage_work                                         | 0          | 36         |
+-----------------------------------------------------------------------+------------+------------+


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <oliver.sang@intel.com>


[  106.616652] WARNING: CPU: 1 PID: 173 at drivers/gpu/drm/drm_fb_helper.c:434 drm_fb_helper_damage_work+0x371/0x390
[  106.627732] Modules linked in:
[  106.632419] CPU: 1 PID: 173 Comm: kworker/1:2 Not tainted 5.10.0-rc4-next-20201120-00007-g6a1b34c0a339 #3
[  106.637806] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[  106.642853] Workqueue: events drm_fb_helper_damage_work
[  106.647664] EIP: drm_fb_helper_damage_work+0x371/0x390
[  106.652305] Code: b1 17 c7 01 68 bd 5b 2d c5 53 50 68 55 21 2d c5 83 15 44 b1 17 c7 00 e8 ae bc b1 01 83 05 48 b1 17 c7 01 83 15 4c b1 17 c7 00 <0f> 0b 83 05 50 b1 17 c7 01 83 15 54 b1 17 c7 00 83 c4 10 e9 78 fd
[  106.663517] EAX: 0000002d EBX: c8730520 ECX: 00000847 EDX: 00000000
[  106.668423] ESI: ca987000 EDI: cab274d8 EBP: f62f5f20 ESP: f62f5ee8
[  106.673214] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010246
[  106.678295] CR0: 80050033 CR2: 00000000 CR3: 063a7000 CR4: 000406d0
[  106.683160] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  106.687967] DR6: fffe0ff0 DR7: 00000400
[  106.690763] Call Trace:
[  106.693394]  process_one_work+0x3ea/0xaa0
[  106.693501] ixgbevf: Intel(R) 10 Gigabit PCI Express Virtual Function Network Driver
[  106.695300]  worker_thread+0x330/0x900
[  106.697406] ixgbevf: Copyright (c) 2009 - 2018 Intel Corporation.
[  106.702963]  kthread+0x190/0x210
[  106.705709]  ? rescuer_thread+0x650/0x650
[  106.708379]  ? kthread_insert_work_sanity_check+0x120/0x120
[  106.711271]  ret_from_fork+0x1c/0x30
[  106.713973] ---[ end trace dd528799d3369ac1 ]---


To reproduce:

        # build kernel
	cd linux
	cp config-5.10.0-rc4-next-20201120-00007-g6a1b34c0a339 .config
	make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 olddefconfig prepare modules_prepare bzImage

        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,
Oliver Sang