Re: [PATCH v4 5/8] vhost: Add kthread support in function vhost_worker_queue()

[Stefano Garzarella]

On Wed, Dec 11, 2024 at 12:41:44AM +0800, Cindy Lu wrote:
The function vhost_worker_queue() uses a function pointer in
vhost_worker, which is initialized based on the inherit_owner
value.
Signed-off-by: Cindy Lu <l...@redhat.com>
---
drivers/vhost/vhost.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 0175bbf4d8b3..d1aec41bcd56 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -237,13 +237,16 @@ EXPORT_SYMBOL_GPL(vhost_poll_stop);
static void vhost_worker_queue(struct vhost_worker *worker,
                               struct vhost_work *work)
{
+       if (!worker)
+               return;
+

In which scenario can `worker` be NULL?

I would like to better understand why it couldn't happen before and now 
it can.

Thanks,
Stefano

        if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
                /* We can only add the work to the list after we're
                 * sure it was not in the list.
                 * test_and_set_bit() implies a memory barrier.
                 */
                llist_add(&work->node, &worker->work_list);
-               vhost_task_wake(worker->vtsk);
+               worker->task_wakeup(worker);
        }
}

--
2.45.0