On Mon, Jan 17, 2022 at 02:40:11PM +0800, Jason Wang wrote: > > 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 Hmm I think you are right. David, I will drop this for now. Up to you to consider whether some central capability will be helpful as a replacement for the virtio-mem specific "removing" flag. > > > virtio_reset_device(vdev); > > vdev->config->del_vqs(vdev); _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
