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. Fixing this comprehensively needs some thought, and new APIs. Let's at least handle the specific case of virtio_console removal that was reported in the field. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1786239 Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> --- drivers/char/virtio_console.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 7eaf303a7a86..c852ce0b4d56 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1956,6 +1956,12 @@ static void virtcons_remove(struct virtio_device *vdev) list_del(&portdev->list); spin_unlock_irq(&pdrvdata_lock); + /* Device is going away, exit any polling for buffers */ + virtio_break_device(vdev); + if (use_multiport(portdev)) + flush_work(&portdev->control_work); + else + flush_work(&portdev->config_work); /* Disable interrupts for vqs */ vdev->config->reset(vdev); /* Finish up work that's lined up */ -- MST _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
