syzbot

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WARNING: CPU: 0 PID: 7098 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: 0 PID: 7098 Comm: syz.2.262 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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 ad 28 a0 fc 4c 89 33 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 88 b3 47 fc <0f> 0b eb ea 44 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c ba fe ff ff 4c
RSP: 0018:ffffc900032372c8 EFLAGS: 00010246
RAX: ffffffff853f31c8 RBX: ffffc90003237440 RCX: 0000000000080000
RDX: ffffc9000e48f000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: 1ffff92000646e88 R08: ffffc90003c9a000 R09: 0000000000000000
R10: ffffc90003c9a000 R11: 0000000000000000 R12: 0000004749493592
R13: dffffc0000000000 R14: ffff888020ff8000 R15: 0000004749493592
FS:  00007f915da9d6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000002747a000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp drivers/gpu/drm/drm_vblank.c:877 [inline]
 drm_crtc_next_vblank_start+0x23e/0x490 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+0x21b/0x8f0 drivers/gpu/drm/drm_atomic_helper.c:1630
 drm_atomic_helper_commit+0x5bf/0xaf0 drivers/gpu/drm/drm_atomic_helper.c:2059
 drm_atomic_commit+0x226/0x280 drivers/gpu/drm/drm_atomic.c:1513
 drm_client_modeset_commit_atomic+0x651/0x7b0 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:1383 [inline]
 drm_fb_helper_pan_display+0x3e9/0xbd0 drivers/gpu/drm/drm_fb_helper.c:1443
 fb_pan_display+0x398/0x680 drivers/video/fbdev/core/fbmem.c:731
 bit_update_start+0x4d/0x1e0 drivers/video/fbdev/core/bitblit.c:414
 fbcon_switch+0x14b3/0x1f80 drivers/video/fbdev/core/fbcon.c:2187
 redraw_screen+0x585/0x1000 drivers/tty/vt/vt.c:969
 do_fb_ioctl+0x7a6/0x7f0 drivers/video/fbdev/core/fb_chrdev.c:92
 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:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f915cb9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f915da9d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f915ce16090 RCX: 00007f915cb9ce59
RDX: 0000200000000100 RSI: 0000000000004601 RDI: 0000000000000003
RBP: 00007f915cc32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f915ce16128 R14: 00007f915ce16090 R15: 00007ffef45f8ec8
 </TASK>