------------[ 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.0.0/5316
WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x12e2/0x1550 kernel/locking/mutex.c:821, CPU#0: syz.0.0/5316
Modules linked in:
CPU: 0 UID: 0 PID: 5316 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: a7 7a 90 48 c1 e8 03 0f b6 04 18 84 c0 0f 85 47 02 00 00 83 3d 8b 26 91 04 00 75 13 48 8d 3d ee 22 94 04 48 c7 c6 60 12 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:ffffc9000e497980 EFLAGS: 00010246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88803d9ba580
RDX: 0000000000000000 RSI: ffffffff8c0d1260 RDI: ffffffff907da3f0
RBP: ffffc9000e497b20 R08: ffffffff907aa783 R09: 1ffffffff20f54f0
R10: dffffc0000000000 R11: fffffbfff20f54f1 R12: ffff888034eb51c0
R13: 0000000000000000 R14: 1ffff92001c92f44 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88808c2c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f17fbcb3c80 CR3: 000000004ff0a000 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
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x73a/0x2360 kernel/exit.c:1012
 do_group_exit+0x22d/0x2f0 kernel/exit.c:1155
 __do_sys_exit_group kernel/exit.c:1166 [inline]
 __se_sys_exit_group kernel/exit.c:1164 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1164
 x64_sys_call+0x18c6/0x18d0 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1118f9e159
Code: Unable to access opcode bytes at 0x7f1118f9e12f.
RSP: 002b:00007ffd5ab611b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1118f9e159
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 00007f11191ec3e0
R10: 00007f1119226128 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f11191ec3e0 R14: 0000000000000003 R15: 00007ffd5ab61270
 </TASK>
----------------
Code disassembly (best guess):
   0:	a7                   	cmpsl  %es:(%rdi),%ds:(%rsi)
   1:	7a 90                	jp     0xffffff93
   3:	48 c1 e8 03          	shr    $0x3,%rax
   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 8b 26 91 04 00 	cmpl   $0x0,0x491268b(%rip)        # 0x49126a5
  1a:	75 13                	jne    0x2f
  1c:	48 8d 3d ee 22 94 04 	lea    0x49422ee(%rip),%rdi        # 0x4942311
  23:	48 c7 c6 60 12 0d 8c 	mov    $0xffffffff8c0d1260,%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