------------[ cut here ]------------
WARNING: CPU: 0 PID: 7040 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: 7040 Comm: syz.3.313 Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
RIP: 0010:vkms_get_vblank_timestamp+0x167/0x1b0 drivers/gpu/drm/vkms/vkms_crtc.c:97
Code: c3 fb e8 0c 7f b1 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 0a b4 c3 fb 90 <0f> 0b 90 eb b5 e8 2f 2e 29 fc e9 dc fe ff ff e8 b5 2e 29 fc e9 14
RSP: 0018:ffffc9000c0cf2b0 EFLAGS: 00010283
RAX: 0000000000007207 RBX: ffff8881437e0028 RCX: ffffc9000e253000
RDX: 0000000000080000 RSI: ffffffff85f76ee6 RDI: 0000000000000006
RBP: 0000002318ab7e27 R08: 0000000000000006 R09: 0000002318ab7e27
R10: 0000002318ab7e27 R11: 0000000000000000 R12: ffffc9000c0cf418
R13: 0000002318ab7e27 R14: 0000000000004e20 R15: ffffffff85f76d80
FS:  00007f5628ba56c0(0000) GS:ffff8881249e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c357ef6 CR3: 000000007a6f5000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp+0x102/0x1b0 drivers/gpu/drm/drm_vblank.c:878
 drm_crtc_next_vblank_start+0x182/0x300 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+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+0x231/0x300 drivers/gpu/drm/drm_atomic.c:1518
 drm_client_modeset_commit_atomic+0x69d/0x7e0 drivers/gpu/drm/drm_client_modeset.c:1079
 drm_client_modeset_commit_locked+0x14d/0x580 drivers/gpu/drm/drm_client_modeset.c:1182
 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+0x479/0x7d0 drivers/video/fbdev/core/fbmem.c:191
 fb_set_var+0x860/0x11f0 drivers/video/fbdev/core/fbmem.c:323
 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:906 [inline]
 __se_sys_ioctl fs/ioctl.c:892 [inline]
 __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5627d8e969
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:00007f5628ba5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5627fb6080 RCX: 00007f5627d8e969
RDX: 0000200000000240 RSI: 0000000000004601 RDI: 0000000000000007
RBP: 00007f5627e10ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5627fb6080 R15: 00007ffc053feb08
 </TASK>