------------[ cut here ]------------
[CRTC:35:crtc-0] vblank wait timed out
WARNING: drivers/gpu/drm/drm_atomic_helper.c:1844 at 0x0, CPU#2: kworker/2:1/59
Modules linked in:
CPU: 2 UID: 0 PID: 59 Comm: kworker/2:1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events drm_fb_helper_damage_work
RIP: 0010:drm_atomic_helper_wait_for_vblanks.part.0+0x766/0x8c0 drivers/gpu/drm/drm_atomic_helper.c:1844
Code: 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 04 01 84 c0 74 08 3c 03 0f 8e 3f 01 00 00 48 8d 3d 20 56 42 0b 8b b5 d8 00 00 00 <67> 48 0f b9 3a e9 ed fc ff ff e8 cb 8e 6e fc e9 81 fe ff ff e8 b1
RSP: 0018:ffffc900007af688 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffff11004a6b27e
RDX: ffff888023cae9a0 RSI: 0000000000000023 RDI: ffffffff90915fb0
RBP: ffff888025359318 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 000000005385b602 R12: dffffc0000000000
R13: ffff88804c9d5e00 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888097967000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000c24150c CR3: 000000004deaf000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1818 [inline]
 drm_atomic_helper_commit_tail+0xde/0x110 drivers/gpu/drm/drm_atomic_helper.c:1920
 commit_tail+0x35b/0x400 drivers/gpu/drm/drm_atomic_helper.c:1997
 drm_atomic_helper_commit+0x300/0x380 drivers/gpu/drm/drm_atomic_helper.c:2235
 drm_atomic_commit+0x234/0x300 drivers/gpu/drm/drm_atomic.c:1743
 drm_atomic_helper_dirtyfb+0x5fd/0x780 drivers/gpu/drm/drm_damage_helper.c:183
 drm_fbdev_shmem_helper_fb_dirty+0x1cc/0x310 drivers/gpu/drm/drm_fbdev_shmem.c:117
 drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:346 [inline]
 drm_fb_helper_damage_work+0x2a2/0x5e0 drivers/gpu/drm/drm_fb_helper.c:369
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess), 5 bytes skipped:
   0:	df 48 89             	fisttps -0x77(%rax)
   3:	f9                   	stc
   4:	48 c1 e9 03          	shr    $0x3,%rcx
   8:	0f b6 04 01          	movzbl (%rcx,%rax,1),%eax
   c:	84 c0                	test   %al,%al
   e:	74 08                	je     0x18
  10:	3c 03                	cmp    $0x3,%al
  12:	0f 8e 3f 01 00 00    	jle    0x157
  18:	48 8d 3d 20 56 42 0b 	lea    0xb425620(%rip),%rdi        # 0xb42563f
  1f:	8b b5 d8 00 00 00    	mov    0xd8(%rbp),%esi
* 25:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2a:	e9 ed fc ff ff       	jmp    0xfffffd1c
  2f:	e8 cb 8e 6e fc       	call   0xfc6e8eff
  34:	e9 81 fe ff ff       	jmp    0xfffffeba
  39:	e8                   	.byte 0xe8
  3a:	b1                   	.byte 0xb1