------------[ cut here ]------------
WARNING: CPU: 1 PID: 10608 at drivers/gpu/drm/vkms/vkms_crtc.c:97 vkms_get_vblank_timestamp+0x137/0x160 drivers/gpu/drm/vkms/vkms_crtc.c:97
Modules linked in:
CPU: 1 UID: 0 PID: 10608 Comm: syz.3.10534 Not tainted 6.15.0-rc4-syzkaller-00040-g8bac8898fe39 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:vkms_get_vblank_timestamp+0x137/0x160 drivers/gpu/drm/vkms/vkms_crtc.c:97
Code: 42 80 3c 28 00 74 08 48 89 df e8 c4 52 42 fc 4c 89 33 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 5a 82 e2 fb 90 <0f> 0b 90 eb e3 44 89 e1 80 e1 07 38 c1 0f 8c ff fe ff ff 4c 89 e7
RSP: 0018:ffffc9000bb5f2c8 EFLAGS: 00010283
RAX: ffffffff85dd3b86 RBX: ffffc9000bb5f440 RCX: 0000000000080000
RDX: ffffc90011154000 RSI: 0000000000001dd9 RDI: 0000000000001dda
RBP: 1ffff9200176be88 R08: ffffffff8f7d9f77 R09: 1ffffffff1efb3ee
R10: dffffc0000000000 R11: ffffffff85dd3a50 R12: 000002d6795b31e2
R13: dffffc0000000000 R14: ffff8880203c4028 R15: 000002d6795b31e2
FS:  00007f2a8e3b06c0(0000) GS:ffff888126203000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000032000 CR3: 0000000059ace000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp drivers/gpu/drm/drm_vblank.c:878 [inline]
 drm_crtc_next_vblank_start+0x223/0x470 drivers/gpu/drm/drm_vblank.c:1012
 set_fence_deadline drivers/gpu/drm/drm_atomic_helper.c:1596 [inline]
 drm_atomic_helper_wait_for_fences+0x265/0x8c0 drivers/gpu/drm/drm_atomic_helper.c:1643
 commit_tail+0x79/0x3a0 drivers/gpu/drm/drm_atomic_helper.c:1857
 drm_atomic_helper_commit+0xa6b/0xb10 drivers/gpu/drm/drm_atomic_helper.c:2111
 drm_atomic_commit+0x25f/0x2c0 drivers/gpu/drm/drm_atomic.c:1518
 drm_client_modeset_commit_atomic+0x620/0x760 drivers/gpu/drm/drm_client_modeset.c:1079
 drm_client_modeset_commit_locked+0xcb/0x4d0 drivers/gpu/drm/drm_client_modeset.c:1182
 drm_client_modeset_commit+0x4a/0x70 drivers/gpu/drm/drm_client_modeset.c:1208
 __drm_fb_helper_restore_fbdev_mode_unlocked+0x9d/0x1b0 drivers/gpu/drm/drm_fb_helper.c:237
 drm_fb_helper_set_par+0xaf/0x100 drivers/gpu/drm/drm_fb_helper.c:1359
 fb_set_var+0x818/0xf60 drivers/video/fbdev/core/fbmem.c:312
 do_fb_ioctl+0x63b/0x750 drivers/video/fbdev/core/fb_chrdev.c:90
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2a8d58e969
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:00007f2a8e3b0038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2a8d7b6160 RCX: 00007f2a8d58e969
RDX: 0000200000000380 RSI: 0000000000004601 RDI: 0000000000000006
RBP: 00007f2a8d610ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2a8d7b6160 R15: 00007fff4ccd4978
 </TASK>