在 2022/1/15 上午5:43, Michael S. Tsirkin 写道:
A common pattern for device reset is currently:
vdev->config->reset(vdev);
.. cleanup ..
reset prevents new interrupts from arriving and waits for interrupt
handlers to finish.
However if - as is common - the handler queues a work request which is
flushed during the cleanup stage, we have code adding buffers / trying
to get buffers while device is reset. Not good.
This was reproduced by running
modprobe virtio_console
modprobe -r virtio_console
in a loop, and this reasoning seems to apply to virtio mem though
I could not reproduce it there.
Fix this up by calling virtio_break_device + flush before reset.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/virtio/virtio_mem.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 38becd8d578c..33b8a118a3ae 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -2888,6 +2888,8 @@ static void virtio_mem_remove(struct virtio_device *vdev)
virtio_mem_deinit_hotplug(vm);
/* reset the device and cleanup the queues */
+ virtio_break_device(vdev);
+ flush_work(&vm->wq);
We set vm->removing to true and call cancel_work_sync() in
virtio_mem_deinit_hotplug(). Isn't is sufficient?
Thanks
virtio_reset_device(vdev);
vdev->config->del_vqs(vdev);
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