------------[ cut here ]------------
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common kernel/locking/mutex.c:625 [inline], CPU#0: syz.0.0/5328
WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x12e2/0x1550 kernel/locking/mutex.c:821, CPU#0: syz.0.0/5328
Modules linked in:
CPU: 0 UID: 0 PID: 5328 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline]
RIP: 0010:__mutex_lock+0x12e9/0x1550 kernel/locking/mutex.c:821
Code: 6b 7a 90 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 47 02 00 00 83 3d 2b 8b 92 04 00 75 13 48 8d 3d ee 86 95 04 48 c7 c6 80 0f 0d 8c <67> 48 0f b9 3a 90 e9 6b ee ff ff 90 0f 0b 90 e9 3e f2 ff ff 90 0f
RSP: 0018:ffffc9000dadfae0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88803c5aa580
RDX: 0000000000000000 RSI: ffffffff8c0d0f80 RDI: ffffffff907d6750
RBP: ffffc9000dadfc80 R08: ffffffff907a6b83 R09: 1ffffffff20f4d70
R10: dffffc0000000000 R11: fffffbfff20f4d71 R12: ffff888034ef51c0
R13: 0000000000000000 R14: 1ffff92001b5bf70 R15: 0000000000000000
FS:  000055557d010540(0000) GS:ffff88808c2cd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055e50f6c0cf0 CR3: 00000000437f1000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 virtio_gpu_remove_from_restore_list drivers/gpu/drm/virtio/virtgpu_object.c:70 [inline]
 virtio_gpu_free_object+0x90/0x1d0 drivers/gpu/drm/virtio/virtgpu_object.c:106
 kref_put include/linux/kref.h:65 [inline]
 __drm_gem_object_put include/drm/drm_gem.h:562 [inline]
 drm_gem_object_put include/drm/drm_gem.h:575 [inline]
 drm_client_buffer_delete+0x183/0x2d0 drivers/gpu/drm/drm_client.c:201
 drm_fbdev_shmem_fb_destroy+0xb5/0xe0 drivers/gpu/drm/drm_fbdev_shmem.c:67
 fb_release+0x11d/0x140 drivers/video/fbdev/core/fb_chrdev.c:381
 __fput+0x418/0xa50 fs/file_table.c:512
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
 do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6b0e19e159
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:00007ffea2e83568 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f6b0e427da0 RCX: 00007f6b0e19e159
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f6b0e427da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007f6b0e427cb0 R11: 0000000000000246 R12: 0000000000019248
R13: 00007f6b0e42618c R14: 00000000000190a6 R15: 00007f6b0e426180
 </TASK>
----------------
Code disassembly (best guess):
   0:	6b 7a 90 48          	imul   $0x48,-0x70(%rdx),%edi
   4:	c1 e8 03             	shr    $0x3,%eax
   7:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax
   b:	84 c0                	test   %al,%al
   d:	0f 85 47 02 00 00    	jne    0x25a
  13:	83 3d 2b 8b 92 04 00 	cmpl   $0x0,0x4928b2b(%rip)        # 0x4928b45
  1a:	75 13                	jne    0x2f
  1c:	48 8d 3d ee 86 95 04 	lea    0x49586ee(%rip),%rdi        # 0x4958711
  23:	48 c7 c6 80 0f 0d 8c 	mov    $0xffffffff8c0d0f80,%rsi
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	90                   	nop
  30:	e9 6b ee ff ff       	jmp    0xffffeea0
  35:	90                   	nop
  36:	0f 0b                	ud2
  38:	90                   	nop
  39:	e9 3e f2 ff ff       	jmp    0xfffff27c
  3e:	90                   	nop
  3f:	0f                   	.byte 0xf