syzbot

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WARNING: CPU: 0 PID: 12936 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: 12936 Comm: syz.3.1949 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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 1d 7b 9f fc 4c 89 33 b0 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 78 4b 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:ffffc9000bc6f2e8 EFLAGS: 00010293
RAX: ffffffff853fd0e8 RBX: ffffc9000bc6f460 RCX: ffff888077a98000
RDX: 0000000000000000 RSI: 000000f3b4aae992 RDI: 000000f3b4aae992
RBP: 1ffff9200178de8c R08: ffffc90003d4a000 R09: 0000000000000000
R10: ffffc90003d4a000 R11: 0000000000000000 R12: 000000f3b4aae992
R13: dffffc0000000000 R14: ffff8880213d0000 R15: 000000f3b4aae992
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc2f03f9d58 CR3: 000000002bad8000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 drm_crtc_get_last_vbltimestamp drivers/gpu/drm/drm_vblank.c:877 [inline]
 drm_crtc_next_vblank_start+0x22b/0x480 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/0x8e0 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+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
 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+0x1d4/0x260 kernel/task_work.c:245
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0x95a/0x2460 kernel/exit.c:883
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 get_signal+0x12fc/0x13f0 kernel/signal.c:2902
 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/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+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb23e55cfce
Code: Unable to access opcode bytes at 0x7fb23e55cfa4.
RSP: 002b:00007ffc026d9bb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00005555636e3500 RCX: 00007fb23e55cfce
RDX: 00007ffc026d9c10 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fb23e817da0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000010001c
R13: 00007fb23e81609c R14: 00000000000ff463 R15: 00007ffc026d9d40
 </TASK>