------------[ cut here ]------------
WARNING: CPU: 0 PID: 8100 at drivers/gpu/drm/vkms/vkms_crtc.c:97 vkms_get_vblank_timestamp+0x167/0x1b0 drivers/gpu/drm/vkms/vkms_crtc.c:97
Modules linked in:
CPU: 0 UID: 0 PID: 8100 Comm: syz.0.633 Not tainted 6.16.0-rc6-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:vkms_get_vblank_timestamp+0x167/0x1b0 drivers/gpu/drm/vkms/vkms_crtc.c:97
Code: b6 fb e8 bc 95 a4 fb 4c 89 e1 48 ba 00 00 00 00 00 fc ff df 48 c1 e9 03 80 3c 11 00 75 43 49 89 04 24 eb c0 e8 fa f1 b6 fb 90 <0f> 0b 90 eb b5 e8 7f cb 1d fc e9 dc fe ff ff e8 05 cc 1d fc e9 14
RSP: 0018:ffffc90002ff75c0 EFLAGS: 00010287
RAX: 0000000000000e81 RBX: ffff888141b50028 RCX: ffffc9000dd75000
RDX: 0000000000080000 RSI: ffffffff86050086 RDI: 0000000000000006
RBP: 00000038c387a485 R08: 0000000000000006 R09: 00000038c387a485
R10: 00000038c387a485 R11: 0000000000000000 R12: ffffc90002ff7728
R13: 00000038c387a485 R14: 0000000000004e20 R15: ffffffff8604ff20
FS:  00007f7f1abde6c0(0000) GS:ffff888124713000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000514ff4 CR3: 000000002b002000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp+0x102/0x1b0 drivers/gpu/drm/drm_vblank.c:879
 drm_crtc_next_vblank_start+0x182/0x300 drivers/gpu/drm/drm_vblank.c:1013
 set_fence_deadline drivers/gpu/drm/drm_atomic_helper.c:1596 [inline]
 drm_atomic_helper_wait_for_fences+0x203/0x830 drivers/gpu/drm/drm_atomic_helper.c:1643
 drm_atomic_helper_commit+0x1cf/0x380 drivers/gpu/drm/drm_atomic_helper.c:2072
 drm_atomic_commit+0x234/0x300 drivers/gpu/drm/drm_atomic.c:1577
 drm_client_modeset_commit_atomic+0x69d/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1101
 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1204
 pan_display_atomic drivers/gpu/drm/drm_fb_helper.c:1387 [inline]
 drm_fb_helper_pan_display+0x32d/0xa40 drivers/gpu/drm/drm_fb_helper.c:1447
 fb_pan_display+0x47c/0x7d0 drivers/video/fbdev/core/fbmem.c:193
 bit_update_start+0x49/0x1f0 drivers/video/fbdev/core/bitblit.c:380
 fbcon_modechanged+0x5a8/0x700 drivers/video/fbdev/core/fbcon.c:2692
 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:2741
 do_fb_ioctl+0x787/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:92
 fb_ioctl+0xe5/0x150 drivers/video/fbdev/core/fb_chrdev.c:169
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f19d8e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f1abde038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7f19fb6080 RCX: 00007f7f19d8e929
RDX: 0000200000000040 RSI: 0000000000004601 RDI: 0000000000000004
RBP: 00007f7f19e10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7f19fb6080 R15: 00007fff74157218
 </TASK>