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WARNING: CPU: 1 PID: 6299 at drivers/gpu/drm/vkms/vkms_crtc.c:97 vkms_get_vblank_timestamp+0x128/0x16c drivers/gpu/drm/vkms/vkms_crtc.c:110
Modules linked in:
CPU: 1 UID: 0 PID: 6299 Comm: syz.2.1008 Not tainted syzkaller #0 PREEMPT 
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : vkms_get_vblank_timestamp+0x128/0x16c drivers/gpu/drm/vkms/vkms_crtc.c:97
lr : vkms_get_vblank_timestamp+0x20/0x16c drivers/gpu/drm/vkms/vkms_crtc.c:88
sp : ffff8000a2b06bb0
x29: ffff8000a2b06bb0 x28: ffff00001857bc00 x27: 0000000000000003
x26: ffff000014248080 x25: 0000000000000000 x24: 1fffe00001ee3538
x23: ffff800085b53700 x22: ffff8000a2b06d80 x21: 0000013f9819f730
x20: ffff000014248080 x19: ffff00000f71a880 x18: 0000000000000002
x17: ffff7fffe2f40000 x16: ffff00006a08a504 x15: 0000000000000000
x14: 1fffe0000d413e59 x13: 0000000000000000 x12: ffff700011a5c9f1
x11: 1ffff00011a5c9f0 x10: ffff700011a5c9f0 x9 : dfff800000000000
x8 : 0000000041b58ab3 x7 : ffff700014560d86 x6 : dfff800000000000
x5 : 0000000000000000 x4 : 1fffe00001ee354a x3 : 0000000000000000
x2 : 1fffe00001ee3535 x1 : 0000000000000000 x0 : 0000013f9819f730
Call trace:
 vkms_get_vblank_timestamp+0x128/0x16c drivers/gpu/drm/vkms/vkms_crtc.c:110 (P)
 drm_crtc_get_last_vbltimestamp+0x140/0x184 drivers/gpu/drm/drm_vblank.c:879
 drm_crtc_next_vblank_start+0x11c/0x244 drivers/gpu/drm/drm_vblank.c:1013
 set_fence_deadline drivers/gpu/drm/drm_atomic_helper.c:1718 [inline]
 drm_atomic_helper_wait_for_fences+0x184/0x614 drivers/gpu/drm/drm_atomic_helper.c:1765
 commit_tail+0x74/0x3e0 drivers/gpu/drm/drm_atomic_helper.c:1979
 drm_atomic_helper_commit+0x260/0x2b4 drivers/gpu/drm/drm_atomic_helper.c:2233
 drm_atomic_commit+0x18c/0x23c drivers/gpu/drm/drm_atomic.c:1577
 drm_client_modeset_commit_atomic+0x4a4/0x5f8 drivers/gpu/drm/drm_client_modeset.c:1103
 drm_client_modeset_commit_locked+0x108/0x3f8 drivers/gpu/drm/drm_client_modeset.c:1206
 pan_display_atomic drivers/gpu/drm/drm_fb_helper.c:1388 [inline]
 drm_fb_helper_pan_display+0x260/0x844 drivers/gpu/drm/drm_fb_helper.c:1448
 fb_pan_display+0x1d0/0x5f8 drivers/video/fbdev/core/fbmem.c:193
 fb_set_var+0x5f8/0xf70 drivers/video/fbdev/core/fbmem.c:330
 fbcon_resize+0x94c/0xd1c drivers/video/fbdev/core/fbcon.c:2082
 resize_screen drivers/tty/vt/vt.c:1121 [inline]
 vc_do_resize+0x290/0xdcc drivers/tty/vt/vt.c:1201
 __vc_resize+0x44/0x6c drivers/tty/vt/vt.c:1303
 vt_ioctl+0xf30/0x24b8 drivers/tty/vt/vt_ioctl.c:911
 tty_ioctl+0x1c8/0x14f8 drivers/tty/tty_io.c:2792
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x124/0x1a4 fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x288 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
irq event stamp: 2670
hardirqs last  enabled at (2669): [<ffff8000854932a4>] irqentry_exit+0x48/0x188 kernel/entry/common.c:214
hardirqs last disabled at (2670): [<ffff80008548c6e4>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:434
softirqs last  enabled at (2526): [<ffff8000801c2c60>] softirq_handle_end kernel/softirq.c:468 [inline]
softirqs last  enabled at (2526): [<ffff8000801c2c60>] handle_softirqs+0x88c/0xdb4 kernel/softirq.c:650
softirqs last disabled at (2519): [<ffff800080010850>] __do_softirq+0x14/0x20 kernel/softirq.c:656
---[ end trace 0000000000000000 ]---