syzbot

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WARNING: CPU: 0 PID: 6366 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: 6366 Comm: syz.1.98 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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 2d b8 ab fc 4c 89 33 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 88 49 54 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:ffffc9000485f4a8 EFLAGS: 00010287
RAX: ffffffff85314738 RBX: ffffc9000485f620 RCX: 0000000000080000
RDX: ffffc9000e450000 RSI: 0000000000002d65 RDI: 0000000000002d66
RBP: 1ffff9200090bec4 R08: ffffc9001a202000 R09: 0000000000000000
R10: ffffc9001a202000 R11: 0000000000000000 R12: 0000002874795eb1
R13: dffffc0000000000 R14: ffff888021084000 R15: 0000002874795eb1
FS:  00007f4e272316c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fab7ccb4e9c CR3: 0000000060b0a000 CR4: 00000000003506f0
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
 drm_client_modeset_commit+0x4a/0x70 drivers/gpu/drm/drm_client_modeset.c:1186
 __drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:251 [inline]
 drm_fb_helper_restore_fbdev_mode_unlocked drivers/gpu/drm/drm_fb_helper.c:278 [inline]
 drm_fb_helper_lastclose+0x9f/0x150 drivers/gpu/drm/drm_fb_helper.c:2018
 drm_fbdev_generic_client_restore+0x34/0x40 drivers/gpu/drm/drm_fbdev_generic.c:257
 drm_client_dev_restore+0x138/0x270 drivers/gpu/drm/drm_client.c:257
 drm_lastclose drivers/gpu/drm/drm_file.c:466 [inline]
 drm_release+0x4bd/0x670 drivers/gpu/drm/drm_file.c:497
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 get_signal+0x1235/0x1400 kernel/signal.c:2678
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4e2638f749
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:00007f4e27231038 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: fffffffffffffe00 RBX: 00007f4e265e6090 RCX: 00007f4e2638f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000a
RBP: 00007f4e26413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000078f2a36b R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4e265e6128 R14: 00007f4e265e6090 R15: 00007fff9578d4c8
 </TASK>