------------[ cut here ]------------
WARNING: CPU: 1 PID: 16563 at drivers/gpu/drm/vkms/vkms_crtc.c:97 vkms_get_vblank_timestamp+0x17d/0x1a0 drivers/gpu/drm/vkms/vkms_crtc.c:97
Modules linked in:
CPU: 1 UID: 0 PID: 16563 Comm: syz.2.2605 Not tainted 6.15.0-rc2-syzkaller-00037-g834a4a689699 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:vkms_get_vblank_timestamp+0x17d/0x1a0 drivers/gpu/drm/vkms/vkms_crtc.c:97
Code: ff df 80 3c 08 00 74 08 4c 89 f7 e8 dd 60 ea fb 49 89 1e b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 44 b7 82 fb 90 <0f> 0b 90 eb e4 89 d9 80 e1 07 38 c1 0f 8c b9 fe ff ff 48 89 df e8
RSP: 0000:ffffc9000535f288 EFLAGS: 00010283
RAX: ffffffff86408d2c RBX: 00000176934c21ba RCX: 0000000000080000
RDX: ffffc9000fdc9000 RSI: 000000000000f2db RDI: 000000000000f2dc
RBP: ffffc9000535f420 R08: ffffffff86408c91 R09: 0000000000000000
R10: ffffc90003759000 R11: ffffffff86408bb0 R12: 00000176934c21ba
R13: ffff88801e767150 R14: 1ffff92000a6be84 R15: ffff88801e774028
FS:  00007f5861c0d6c0(0000) GS:ffff8881250c9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd7796d56c0 CR3: 000000004d0be000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp drivers/gpu/drm/drm_vblank.c:878 [inline]
 drm_crtc_next_vblank_start+0x255/0x4f0 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+0x27c/0x8e0 drivers/gpu/drm/drm_atomic_helper.c:1643
 drm_atomic_helper_commit+0x53f/0xa00 drivers/gpu/drm/drm_atomic_helper.c:2072
 drm_atomic_commit+0x296/0x2f0 drivers/gpu/drm/drm_atomic.c:1518
 drm_client_modeset_commit_atomic+0x677/0x7d0 drivers/gpu/drm/drm_client_modeset.c:1079
 drm_client_modeset_commit_locked+0xe0/0x520 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+0x3e8/0xc20 drivers/gpu/drm/drm_fb_helper.c:1447
 fb_pan_display+0x3a3/0x680 drivers/video/fbdev/core/fbmem.c:191
 bit_update_start+0x4d/0x1c0 drivers/video/fbdev/core/bitblit.c:380
 fbcon_switch+0x144d/0x2260 drivers/video/fbdev/core/fbcon.c:2187
 redraw_screen+0x55a/0xed0 drivers/tty/vt/vt.c:957
 do_fb_ioctl+0x74c/0x7e0 drivers/video/fbdev/core/fb_chrdev.c:92
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5860d8d169
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:00007f5861c0d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5860fa6160 RCX: 00007f5860d8d169
RDX: 0000200000000380 RSI: 0000000000004601 RDI: 0000000000000008
RBP: 00007f5860e0e990 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5860fa6160 R15: 00007ffcf1ace2f8
 </TASK>