------------[ cut here ]------------
WARNING: CPU: 1 PID: 20770 at drivers/gpu/drm/vkms/vkms_crtc.c:103 vkms_get_vblank_timestamp+0x188/0x1d0 drivers/gpu/drm/vkms/vkms_crtc.c:103
Modules linked in:
CPU: 1 PID: 20770 Comm: syz.2.4437 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:vkms_get_vblank_timestamp+0x188/0x1d0 drivers/gpu/drm/vkms/vkms_crtc.c:103
Code: 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 7d 8b ac fc 4c 89 33 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 c8 44 55 fc <0f> 0b eb ea 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c ba fe ff ff 4c
RSP: 0000:ffffc9000c427328 EFLAGS: 00010283
RAX: ffffffff853050c8 RBX: ffffc9000c4274a0 RCX: 0000000000080000
RDX: ffffc90010162000 RSI: 00000000000059fa RDI: 00000000000059fb
RBP: 1ffff92001884e94 R08: ffffc90004bb9000 R09: 0000000000000000
R10: ffffc90004bb9000 R11: 0000000000000000 R12: 00000137679ba989
R13: dffffc0000000000 R14: ffff888021004000 R15: 00000137679ba989
FS:  00007f2799c166c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c427ab7 CR3: 000000006087a000 CR4: 00000000003506e0
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:877 [inline]
 drm_crtc_next_vblank_start+0x21f/0x450 drivers/gpu/drm/drm_vblank.c:1012
 set_fence_deadline drivers/gpu/drm/drm_atomic_helper.c:1583 [inline]
 drm_atomic_helper_wait_for_fences+0x263/0x8b0 drivers/gpu/drm/drm_atomic_helper.c:1630
 drm_atomic_helper_commit+0x5b5/0xae0 drivers/gpu/drm/drm_atomic_helper.c:2059
 drm_atomic_commit+0x24c/0x2a0 drivers/gpu/drm/drm_atomic.c:1513
 drm_client_modeset_commit_atomic+0x621/0x760 drivers/gpu/drm/drm_client_modeset.c:1057
 drm_client_modeset_commit_locked+0xcb/0x4c0 drivers/gpu/drm/drm_client_modeset.c:1160
 pan_display_atomic drivers/gpu/drm/drm_fb_helper.c:1386 [inline]
 drm_fb_helper_pan_display+0x3e7/0xbd0 drivers/gpu/drm/drm_fb_helper.c:1446
 fb_pan_display+0x39f/0x690 drivers/video/fbdev/core/fbmem.c:731
 fb_set_var+0x7fa/0xf20 drivers/video/fbdev/core/fbmem.c:863
 do_fb_ioctl+0x636/0x740 drivers/video/fbdev/core/fb_chrdev.c:90
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2798d8eb69
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:00007f2799c16038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2798fb6240 RCX: 00007f2798d8eb69
RDX: 0000200000000380 RSI: 0000000000004601 RDI: 000000000000000a
RBP: 00007f2798e11df1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f2798fb6240 R15: 00007ffece0b0f28
 </TASK>