=============================================================================
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.2.3186/18405 is trying to acquire lock:
ffffffff8ecf5cc0 (console_owner){-.-.}-{0:0}, at: console_lock_spinning_enable+0x61/0x80 kernel/printk/printk.c:1902

but task is already holding lock:
ffff88802743d618 (&n->list_lock){-.-.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:377 [inline]
ffff88802743d618 (&n->list_lock){-.-.}-{3:3}, at: free_partial mm/slub.c:8004 [inline]
ffff88802743d618 (&n->list_lock){-.-.}-{3:3}, at: __kmem_cache_shutdown+0x10c/0x330 mm/slub.c:8053

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&n->list_lock){-.-.}-{3:3}:
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
       get_partial_node_bulk mm/slub.c:3746 [inline]
       __refill_objects_node+0x120/0xaa0 mm/slub.c:7164
       refill_objects+0x58/0x410 mm/slub.c:7292
       refill_sheaf mm/slub.c:2805 [inline]
       __pcs_replace_empty_main+0x372/0x680 mm/slub.c:4677
       alloc_from_pcs mm/slub.c:4775 [inline]
       slab_alloc_node mm/slub.c:4907 [inline]
       __do_kmalloc_node mm/slub.c:5336 [inline]
       __kmalloc_noprof+0x66b/0x820 mm/slub.c:5362
       _kmalloc_noprof include/linux/slab.h:992 [inline]
       tty_buffer_alloc+0x29f/0x320 drivers/tty/tty_buffer.c:187
       __tty_buffer_request_room+0x129/0x2c0 drivers/tty/tty_buffer.c:280
       __tty_insert_flip_string_flags+0xdb/0x3f0 drivers/tty/tty_buffer.c:316
       tty_insert_flip_string_fixed_flag include/linux/tty_flip.h:35 [inline]
       tty_insert_flip_string include/linux/tty_flip.h:83 [inline]
       tty_insert_flip_string_and_push_buffer+0x9c/0x230 drivers/tty/tty_buffer.c:565
       pty_write+0xd2/0x100 drivers/tty/pty.c:116
       tty_put_char+0x130/0x160 drivers/tty/tty_io.c:3127
       do_output_char+0x155/0x850 drivers/tty/n_tty.c:459
       __process_echoes+0x21c/0xb10 drivers/tty/n_tty.c:697
       flush_echoes drivers/tty/n_tty.c:785 [inline]
       __receive_buf drivers/tty/n_tty.c:1618 [inline]
       n_tty_receive_buf_common+0x462/0x1930 drivers/tty/n_tty.c:1715
       tty_ldisc_receive_buf+0xaa/0x1a0 drivers/tty/tty_buffer.c:394
       tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
       receive_buf drivers/tty/tty_buffer.c:452 [inline]
       flush_to_ldisc+0x26b/0x730 drivers/tty/tty_buffer.c:502
       process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
       process_scheduled_works kernel/workqueue.c:3470 [inline]
       worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
       kthread+0x373/0x450 kernel/kthread.c:436
       ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&port->lock#2){-...}-{3:3}:
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       __raw_spin_lock_irq_disable include/linux/spinlock_api_smp.h:174 [inline]
       _raw_spin_lock_irq_disable+0x5e/0x90 kernel/locking/spinlock.c:197
       spin_lock_irq_disable include/linux/spinlock.h:383 [inline]
       class_spinlock_irqsave_constructor include/linux/spinlock.h:641 [inline]
       tty_port_tty_get+0x1f/0xf0 drivers/tty/tty_port.c:322
       class_tty_port_tty_constructor include/linux/tty_port.h:293 [inline]
       tty_port_default_wakeup+0x15/0x60 drivers/tty/tty_port.c:66
       serial8250_tx_chars+0x68f/0x860 drivers/tty/serial/8250/8250_port.c:1723
       __start_tx+0x3e4/0x490 drivers/tty/serial/8250/8250_port.c:1430
       serial8250_start_tx+0x368/0x540 drivers/tty/serial/8250/8250_port.c:1539
       __uart_start+0x295/0x510 drivers/tty/serial/serial_core.c:161
       uart_write+0x211/0xb20 drivers/tty/serial/serial_core.c:629
       process_output_block drivers/tty/n_tty.c:557 [inline]
       n_tty_write+0x431/0x1160 drivers/tty/n_tty.c:2366
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write.isra.0+0x4d2/0x890 drivers/tty/tty_io.c:1054
       tty_write drivers/tty/tty_io.c:1075 [inline]
       redirected_tty_write drivers/tty/tty_io.c:1098 [inline]
       redirected_tty_write+0xd4/0x120 drivers/tty/tty_io.c:1078
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x6af/0x1050 fs/read_write.c:687
       ksys_write+0x12a/0x250 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&port_lock_key){-.-.}-{3:3}:
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:155 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:181
       uart_port_lock_irqsave include/linux/serial_core.h:719 [inline]
       serial8250_console_write+0x177/0x1a50 drivers/tty/serial/8250/8250_port.c:3344
       console_emit_next_record kernel/printk/printk.c:3183 [inline]
       console_flush_one_record+0x78e/0xf10 kernel/printk/printk.c:3268
       console_flush_all kernel/printk/printk.c:3350 [inline]
       __console_flush_and_unlock kernel/printk/printk.c:3380 [inline]
       console_unlock+0x103/0x260 kernel/printk/printk.c:3420
       vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
       _printk+0xcf/0x110 kernel/printk/printk.c:2504
       register_console.cold+0xc0/0x248 kernel/printk/printk.c:4212
       univ8250_console_init+0x6f/0x80 drivers/tty/serial/8250/8250_core.c:515
       console_init+0x3d5/0x5b0 kernel/printk/printk.c:4411
       start_kernel+0x314/0x490 init/main.c:1118
       x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
       x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291
       common_startup_64+0x13e/0x158

-> #0 (console_owner){-.-.}-{0:0}:
       check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
       check_prevs_add kernel/locking/lockdep.c:3300 [inline]
       validate_chain kernel/locking/lockdep.c:3924 [inline]
       __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253
       lock_acquire kernel/locking/lockdep.c:5886 [inline]
       lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
       console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1902
       console_emit_next_record kernel/printk/printk.c:3177 [inline]
       console_flush_one_record+0x737/0xf10 kernel/printk/printk.c:3268
       console_flush_all kernel/printk/printk.c:3350 [inline]
       __console_flush_and_unlock kernel/printk/printk.c:3380 [inline]
       console_unlock+0x103/0x260 kernel/printk/printk.c:3420
       vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
       _printk+0xcf/0x110 kernel/printk/printk.c:2504
       __slab_bug+0x4f/0xb0 mm/slub.c:1145
       slab_bug+0x5d/0x80 mm/slub.c:1156
       list_slab_objects mm/slub.c:7973 [inline]
       free_partial mm/slub.c:8010 [inline]
       __kmem_cache_shutdown.cold+0x39/0x177 mm/slub.c:8053
       kmem_cache_destroy mm/slab_common.c:569 [inline]
       kmem_cache_destroy+0x73/0x190 mm/slab_common.c:527
       virtio_gpu_free_vbufs+0x38/0x80 drivers/gpu/drm/virtio/virtgpu_vq.c:86
       virtio_gpu_release+0x5c/0x1c0 drivers/gpu/drm/virtio/virtgpu_kms.c:312
       drm_dev_release drivers/gpu/drm/drm_drv.c:912 [inline]
       kref_put include/linux/kref.h:65 [inline]
       drm_dev_put.part.0+0xbd/0x140 drivers/gpu/drm/drm_drv.c:948
       drm_dev_put+0x1f/0x30 drivers/gpu/drm/drm_drv.c:947
       virtio_dev_remove+0xb8/0x170 drivers/virtio/virtio.c:375
       device_remove+0xcb/0x180 drivers/base/dd.c:616
       __device_release_driver drivers/base/dd.c:1349 [inline]
       device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
       bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
       device_del+0x376/0x9b0 drivers/base/core.c:3965
       device_unregister+0x1d/0xe0 drivers/base/core.c:4006
       unregister_virtio_device+0x39/0x60 drivers/virtio/virtio.c:607
       virtio_pci_remove+0x7c/0x110 drivers/virtio/virtio_pci_common.c:758
       pci_device_remove+0xb2/0x1d0 drivers/pci/pci-driver.c:512
       device_remove+0xcb/0x180 drivers/base/dd.c:616
       __device_release_driver drivers/base/dd.c:1349 [inline]
       device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
       pci_stop_dev drivers/pci/remove.c:27 [inline]
       pci_stop_bus_device+0x120/0x160 drivers/pci/remove.c:93
       pci_stop_and_remove_bus_device+0x58/0xa0 drivers/pci/remove.c:128
       pci_stop_and_remove_bus_device_locked+0x1a/0x20 drivers/pci/remove.c:136
       remove_store+0x123/0x140 drivers/pci/pci-sysfs.c:524
       dev_attr_store+0x58/0x80 drivers/base/core.c:2509
       sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
       kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
       new_sync_write fs/read_write.c:595 [inline]
       vfs_write+0x6af/0x1050 fs/read_write.c:687
       ksys_write+0x12a/0x250 fs/read_write.c:739
       do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
       do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  console_owner --> &port->lock#2 --> &n->list_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&n->list_lock);
                               lock(&port->lock#2);
                               lock(&n->list_lock);
  lock(console_owner);

 *** DEADLOCK ***

locks held by syz.2.3186/18405: 11, last CPU#1:
 #0: ffff88803d2355f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
 #1: ffff88802b288460 (sb_writers#8){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
 #2: ffff88805c19d080 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336
 #3: ffffffff8fa7d5e0 (pci_rescan_remove_lock){+.+.}-{4:4}, at: pci_stop_and_remove_bus_device_locked+0x12/0x20 drivers/pci/remove.c:135
 #4: ffff8880227ec1f8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #4: ffff8880227ec1f8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #4: ffff8880227ec1f8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
 #5: ffff888025da51b0 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
 #5: ffff888025da51b0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
 #5: ffff888025da51b0 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb2/0x620 drivers/base/dd.c:1369
 #6: ffffffff8ec7a830 (cpu_hotplug_lock){++++}-{0:0}, at: kmem_cache_destroy mm/slab_common.c:556 [inline]
 #6: ffffffff8ec7a830 (cpu_hotplug_lock){++++}-{0:0}, at: kmem_cache_destroy+0x4b/0x190 mm/slab_common.c:527
 #7: ffffffff8ef940c0 (slab_mutex){+.+.}-{4:4}, at: kmem_cache_destroy mm/slab_common.c:557 [inline]
 #7: ffffffff8ef940c0 (slab_mutex){+.+.}-{4:4}, at: kmem_cache_destroy+0x59/0x190 mm/slab_common.c:527
 #8: ffff88802743d618 (&n->list_lock){-.-.}-{3:3}, at: spin_lock_irq include/linux/spinlock.h:377 [inline]
 #8: ffff88802743d618 (&n->list_lock){-.-.}-{3:3}, at: free_partial mm/slub.c:8004 [inline]
 #8: ffff88802743d618 (&n->list_lock){-.-.}-{3:3}, at: __kmem_cache_shutdown+0x10c/0x330 mm/slub.c:8053
 #9: ffffffff8edd6100 (console_lock){+.+.}-{0:0}, at: _printk+0xcf/0x110 kernel/printk/printk.c:2504
 #10: ffffffff8edd6178 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:305 [inline]
 #10: ffffffff8edd6178 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:428 [inline]
 #10: ffffffff8edd6178 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:291 [inline]
 #10: ffffffff8edd6178 (console_srcu){....}-{0:0}, at: console_flush_one_record+0xfd/0xf10 kernel/printk/printk.c:3246

stack backtrace:
CPU: 1 UID: 0 PID: 18405 Comm: syz.2.3186 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_circular_bug.cold+0x178/0x1be kernel/locking/lockdep.c:2059
 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2191
 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3181
 check_prevs_add kernel/locking/lockdep.c:3300 [inline]
 validate_chain kernel/locking/lockdep.c:3924 [inline]
 __lock_acquire+0x1492/0x1ec0 kernel/locking/lockdep.c:5253
 lock_acquire kernel/locking/lockdep.c:5886 [inline]
 lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5843
 console_lock_spinning_enable+0x72/0x80 kernel/printk/printk.c:1902
 console_emit_next_record kernel/printk/printk.c:3177 [inline]
 console_flush_one_record+0x737/0xf10 kernel/printk/printk.c:3268
 console_flush_all kernel/printk/printk.c:3350 [inline]
 __console_flush_and_unlock kernel/printk/printk.c:3380 [inline]
 console_unlock+0x103/0x260 kernel/printk/printk.c:3420
 vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
 _printk+0xcf/0x110 kernel/printk/printk.c:2504
 __slab_bug+0x4f/0xb0 mm/slub.c:1145
 slab_bug+0x5d/0x80 mm/slub.c:1156
 list_slab_objects mm/slub.c:7973 [inline]
 free_partial mm/slub.c:8010 [inline]
 __kmem_cache_shutdown.cold+0x39/0x177 mm/slub.c:8053
 kmem_cache_destroy mm/slab_common.c:569 [inline]
 kmem_cache_destroy+0x73/0x190 mm/slab_common.c:527
 virtio_gpu_free_vbufs+0x38/0x80 drivers/gpu/drm/virtio/virtgpu_vq.c:86
 virtio_gpu_release+0x5c/0x1c0 drivers/gpu/drm/virtio/virtgpu_kms.c:312
 drm_dev_release drivers/gpu/drm/drm_drv.c:912 [inline]
 kref_put include/linux/kref.h:65 [inline]
 drm_dev_put.part.0+0xbd/0x140 drivers/gpu/drm/drm_drv.c:948
 drm_dev_put+0x1f/0x30 drivers/gpu/drm/drm_drv.c:947
 virtio_dev_remove+0xb8/0x170 drivers/virtio/virtio.c:375
 device_remove+0xcb/0x180 drivers/base/dd.c:616
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
 device_del+0x376/0x9b0 drivers/base/core.c:3965
 device_unregister+0x1d/0xe0 drivers/base/core.c:4006
 unregister_virtio_device+0x39/0x60 drivers/virtio/virtio.c:607
 virtio_pci_remove+0x7c/0x110 drivers/virtio/virtio_pci_common.c:758
 pci_device_remove+0xb2/0x1d0 drivers/pci/pci-driver.c:512
 device_remove+0xcb/0x180 drivers/base/dd.c:616
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
 pci_stop_dev drivers/pci/remove.c:27 [inline]
 pci_stop_bus_device+0x120/0x160 drivers/pci/remove.c:93
 pci_stop_and_remove_bus_device+0x58/0xa0 drivers/pci/remove.c:128
 pci_stop_and_remove_bus_device_locked+0x1a/0x20 drivers/pci/remove.c:136
 remove_store+0x123/0x140 drivers/pci/pci-sysfs.c:524
 dev_attr_store+0x58/0x80 drivers/base/core.c:2509
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcec919e0d9
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:00007fceca0fe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcec9425fa0 RCX: 00007fcec919e0d9
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007fcec9235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcec9426038 R14: 00007fcec9425fa0 R15: 00007ffcfec80568
 </TASK>
BUG virtio-gpu-vbufs (Tainted: G             L     ): Objects remaining on __kmem_cache_shutdown()
-----------------------------------------------------------------------------

Object 0xffff8880623d2000 @offset=0
Object 0xffff8880623d2118 @offset=280
Object 0xffff8880623d2230 @offset=560
Slab 0xffffea000188f480 objects=29 used=3 fp=0xffff8880623d2348 flags=0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
------------[ cut here ]------------
1
WARNING: mm/slub.c:1245 at __slab_err+0x15/0x20 mm/slub.c:1245, CPU#1: syz.2.3186/18405
Modules linked in:
CPU: 1 UID: 0 PID: 18405 Comm: syz.2.3186 Tainted: G    B        L      syzkaller #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__slab_err+0x15/0x20 mm/slub.c:1245
Code: 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 e8 5b fd ff ff be 01 00 00 00 bf 05 00 00 00 e8 9c 14 a3 00 90 <0f> 0b 90 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000718f740 EFLAGS: 00010046
RAX: 0000000000080000 RBX: ffffc9000718f790 RCX: ffffc9000cd02000
RDX: 0000000000080000 RSI: ffffffff81c769bd RDI: ffff88805572a580
RBP: ffff88802743d618 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000062616c53 R12: 0000000000001ea0
R13: ffff8880623d3fb8 R14: ffff88802743d600 R15: ffffea000188f480
FS:  00007fceca0fe6c0(0000) GS:ffff8880d5ca2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fae38f5da08 CR3: 000000004ab07000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 list_slab_objects mm/slub.c:7989 [inline]
 free_partial mm/slub.c:8010 [inline]
 __kmem_cache_shutdown.cold+0x16e/0x177 mm/slub.c:8053
 kmem_cache_destroy mm/slab_common.c:569 [inline]
 kmem_cache_destroy+0x73/0x190 mm/slab_common.c:527
 virtio_gpu_free_vbufs+0x38/0x80 drivers/gpu/drm/virtio/virtgpu_vq.c:86
 virtio_gpu_release+0x5c/0x1c0 drivers/gpu/drm/virtio/virtgpu_kms.c:312
 drm_dev_release drivers/gpu/drm/drm_drv.c:912 [inline]
 kref_put include/linux/kref.h:65 [inline]
 drm_dev_put.part.0+0xbd/0x140 drivers/gpu/drm/drm_drv.c:948
 drm_dev_put+0x1f/0x30 drivers/gpu/drm/drm_drv.c:947
 virtio_dev_remove+0xb8/0x170 drivers/virtio/virtio.c:375
 device_remove+0xcb/0x180 drivers/base/dd.c:616
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
 bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
 device_del+0x376/0x9b0 drivers/base/core.c:3965
 device_unregister+0x1d/0xe0 drivers/base/core.c:4006
 unregister_virtio_device+0x39/0x60 drivers/virtio/virtio.c:607
 virtio_pci_remove+0x7c/0x110 drivers/virtio/virtio_pci_common.c:758
 pci_device_remove+0xb2/0x1d0 drivers/pci/pci-driver.c:512
 device_remove+0xcb/0x180 drivers/base/dd.c:616
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
 pci_stop_dev drivers/pci/remove.c:27 [inline]
 pci_stop_bus_device+0x120/0x160 drivers/pci/remove.c:93
 pci_stop_and_remove_bus_device+0x58/0xa0 drivers/pci/remove.c:128
 pci_stop_and_remove_bus_device_locked+0x1a/0x20 drivers/pci/remove.c:136
 remove_store+0x123/0x140 drivers/pci/pci-sysfs.c:524
 dev_attr_store+0x58/0x80 drivers/base/core.c:2509
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcec919e0d9
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:00007fceca0fe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fcec9425fa0 RCX: 00007fcec919e0d9
RDX: 0000000000000001 RSI: 00002000000000c0 RDI: 0000000000000006
RBP: 00007fcec9235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcec9426038 R14: 00007fcec9425fa0 R15: 00007ffcfec80568
 </TASK>