------------[ cut here ]------------
WARNING: CPU: 0 PID: 16724 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: 16724 Comm: syz.8.2825 Not tainted 6.16.0-rc1-syzkaller-00005-g488ef3560196 #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: ba fb e8 4c 85 a7 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 da 17 ba fb 90 <0f> 0b 90 eb b5 e8 7f df 1f fc e9 dc fe ff ff e8 05 e0 1f fc e9 14
RSP: 0018:ffffc9000b1cf338 EFLAGS: 00010287
RAX: 0000000000003aa5 RBX: ffff888140fe4028 RCX: ffffc900141c7000
RDX: 0000000000080000 RSI: ffffffff86020426 RDI: 0000000000000006
RBP: 00000144b4cab092 R08: 0000000000000006 R09: 00000144b4cab092
R10: 00000144b4cab092 R11: 0000000000000001 R12: ffffc9000b1cf4a0
R13: 00000144b4cab092 R14: 0000000000004e20 R15: ffffffff860202c0
FS:  00007fe60d9d56c0(0000) GS:ffff88812475b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3d6859 CR3: 000000007c14b000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp+0x105/0x1b0 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
 commit_tail+0x83/0x400 drivers/gpu/drm/drm_atomic_helper.c:1857
 drm_atomic_helper_commit+0x2fd/0x380 drivers/gpu/drm/drm_atomic_helper.c:2111
 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
 drm_client_modeset_commit+0x4f/0x80 drivers/gpu/drm/drm_client_modeset.c:1230
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:237 [inline]
 __drm_fb_helper_restore_fbdev_mode_unlocked+0x19f/0x200 drivers/gpu/drm/drm_fb_helper.c:216
 drm_fb_helper_set_par+0xd8/0x120 drivers/gpu/drm/drm_fb_helper.c:1359
 fb_set_var+0x822/0x1280 drivers/video/fbdev/core/fbmem.c:319
 do_fb_ioctl+0x745/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:90
 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: 0033:0x7fe60fb8e929
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:00007fe60d9d5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe60fdb6080 RCX: 00007fe60fb8e929
RDX: 0000200000000240 RSI: 0000000000004601 RDI: 0000000000000009
RBP: 00007fe60fc10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe60fdb6080 R15: 00007ffdefcf9af8
 </TASK>