------------[ cut here ]------------
WARNING: CPU: 0 PID: 6015 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: 0 UID: 0 PID: 6015 Comm: syz.1.23 Not tainted 6.15.0-rc7-syzkaller-00142-g4856ebd99715 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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 d4 fa 3c fc 4c 89 33 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d e9 eb 4d 2b fb cc e8 aa fe da 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:ffffc900042a74a8 EFLAGS: 00010287
RAX: ffffffff85e4f326 RBX: ffffc900042a7620 RCX: 0000000000080000
RDX: ffffc9000e013000 RSI: 00000000000187a8 RDI: 00000000000187a9
RBP: 1ffff92000854ec4 R08: ffff88807a9d3517 R09: 1ffff1100f53a6a2
R10: dffffc0000000000 R11: ffffffff85e4f1f0 R12: 00000016e24c5926
R13: dffffc0000000000 R14: ffff888141b6c028 R15: 00000016e24c5926
FS:  00007f9724d426c0(0000) GS:ffff8881260c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555589e55c8 CR3: 0000000030cbd000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp drivers/gpu/drm/drm_vblank.c:878 [inline]
 drm_crtc_next_vblank_start+0x226/0x470 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
 drm_atomic_helper_commit+0x5c7/0xb10 drivers/gpu/drm/drm_atomic_helper.c:2072
 drm_atomic_commit+0x262/0x2c0 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
 pan_display_atomic drivers/gpu/drm/drm_fb_helper.c:1387 [inline]
 drm_fb_helper_pan_display+0x3e7/0xbd0 drivers/gpu/drm/drm_fb_helper.c:1447
 fb_pan_display+0x39e/0x680 drivers/video/fbdev/core/fbmem.c:191
 bit_update_start+0x4d/0x1e0 drivers/video/fbdev/core/bitblit.c:380
 fbcon_modechanged+0xaf6/0x11b0 drivers/video/fbdev/core/fbcon.c:2687
 do_fb_ioctl+0x6fd/0x750 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+0xfc/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: 0033:0x7f9723f8e969
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:00007f9724d42038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f97241b6080 RCX: 00007f9723f8e969
RDX: 0000200000000240 RSI: 0000000000004601 RDI: 0000000000000005
RBP: 00007f9724010ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f97241b6080 R15: 00007ffc6e5e49e8
 </TASK>