On Mon, Jan 27, 2025 at 08:48:03AM -0800, Sean Christopherson wrote: > > > - vhost_task_start(kvm->arch.nx_huge_page_recovery_thread); > > > + if (!nx_thread) > > > + return; > > > + > > > + vhost_task_start(nx_thread); > > > + > > > + /* Make the task visible only once it is fully started. */ > > > + WRITE_ONCE(kvm->arch.nx_huge_page_recovery_thread, nx_thread); > > > > I believe the WRITE_ONCE needs to happen before the vhost_task_start to > > ensure the parameter update callback can see it before it's started. > > It's not clear to me that calling vhost_task_wake() before vhost_task_start() is > allowed, which is why I deliberately waited until the task was started to make it > visible. Though FWIW, doing "vhost_task_wake(nx_thread)" before vhost_task_start() > doesn't explode. Hm, it does look questionable to try to wake a process that hadn't been started yet, but I think it may be okay: task state will be TASK_NEW before vhost_task_start(), which looks like will cause wake_up_process() to do nothing.
