[PATCH] vp_vdpa: fix the crash in hot unplug with vp_vdpa

[Cindy Lu]

While unplugging the vp_vdpa device, the kernel will crash
The root cause is the function vp_modern_get_status() called following the
vp_modern_remove(). So need to change the sequence in vp_vdpa_remove

[  195.016001] Call Trace:
[  195.016233]  <TASK>
[  195.016434]  vp_modern_get_status+0x12/0x20
[  195.016823]  vp_vdpa_reset+0x1b/0x50 [vp_vdpa]
[  195.017238]  virtio_vdpa_reset+0x3c/0x48 [virtio_vdpa]
[  195.017709]  remove_vq_common+0x1f/0x3a0 [virtio_net]
[  195.018178]  virtnet_remove+0x5d/0x70 [virtio_net]
[  195.018618]  virtio_dev_remove+0x3d/0x90
[  195.018986]  device_release_driver_internal+0x1aa/0x230
[  195.019466]  bus_remove_device+0xd8/0x150
[  195.019841]  device_del+0x18b/0x3f0
[  195.020167]  ? kernfs_find_ns+0x35/0xd0
[  195.020526]  device_unregister+0x13/0x60
[  195.020894]  unregister_virtio_device+0x11/0x20
[  195.021311]  device_release_driver_internal+0x1aa/0x230
[  195.021790]  bus_remove_device+0xd8/0x150
[  195.022162]  device_del+0x18b/0x3f0
[  195.022487]  device_unregister+0x13/0x60
[  195.022852]  ? vdpa_dev_remove+0x30/0x30 [vdpa]
[  195.023270]  vp_vdpa_dev_del+0x12/0x20 [vp_vdpa]
[  195.023694]  vdpa_match_remove+0x2b/0x40 [vdpa]
[  195.024115]  bus_for_each_dev+0x78/0xc0
[  195.024471]  vdpa_mgmtdev_unregister+0x65/0x80 [vdpa]
[  195.024937]  vp_vdpa_remove+0x23/0x40 [vp_vdpa]
[  195.025353]  pci_device_remove+0x36/0xa0
[  195.025719]  device_release_driver_internal+0x1aa/0x230
[  195.026201]  pci_stop_bus_device+0x6c/0x90
[  195.026580]  pci_stop_and_remove_bus_device+0xe/0x20
[  195.027039]  disable_slot+0x49/0x90
[  195.027366]  acpiphp_disable_and_eject_slot+0x15/0x90
[  195.027832]  hotplug_event+0xea/0x210
[  195.028171]  ? hotplug_event+0x210/0x210
[  195.028535]  acpiphp_hotplug_notify+0x22/0x80
[  195.028942]  ? hotplug_event+0x210/0x210
[  195.029303]  acpi_device_hotplug+0x8a/0x1d0
[  195.029690]  acpi_hotplug_work_fn+0x1a/0x30
[  195.030077]  process_one_work+0x1e8/0x3c0
[  195.030451]  worker_thread+0x50/0x3b0
[  195.030791]  ? rescuer_thread+0x3a0/0x3a0
[  195.031165]  kthread+0xd9/0x100
[  195.031459]  ? kthread_complete_and_exit+0x20/0x20
[  195.031899]  ret_from_fork+0x22/0x30
[  195.032233]  </TASK>

Fixes: ffbda8e9df10 ("vdpa/vp_vdpa : add vdpa tool support in vp_vdpa")
Tested-by: Lei Yang <leiyang@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
---
 drivers/vdpa/virtio_pci/vp_vdpa.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index 8fe267ca3e76..281287fae89f 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -645,8 +645,8 @@ static void vp_vdpa_remove(struct pci_dev *pdev)
 	struct virtio_pci_modern_device *mdev = NULL;
 
 	mdev = vp_vdpa_mgtdev->mdev;
-	vp_modern_remove(mdev);
 	vdpa_mgmtdev_unregister(&vp_vdpa_mgtdev->mgtdev);
+	vp_modern_remove(mdev);
 	kfree(vp_vdpa_mgtdev->mgtdev.id_table);
 	kfree(mdev);
 	kfree(vp_vdpa_mgtdev);
-- 
2.34.3