Re: [Ping][PATCH v0] vl: flush all task from rcu queue before exiting

[Paolo Bonzini <pbonzini@redhat.com>]

On 11/9/21 08:23, Denis Plotnikov wrote:
> Ping ping!

Looks good, but can you explain why it's okay to call it before 
qemu_chr_cleanup() and user_creatable_cleanup()?

I think a better solution to the ordering problem would be:

   qemu_chr_cleanup();
   user_creatable_cleanup();
   flush_rcu();
   monitor_cleanup();

with something like this:

diff --git a/chardev/char-fe.c b/chardev/char-fe.c
index 7789f7be9c..f0c3ea5447 100644
--- a/chardev/char-fe.c
+++ b/chardev/char-fe.c
@@ -195,6 +195,7 @@ bool qemu_chr_fe_init(CharBackend *b,
      int tag = 0;

      if (s) {
+        object_ref(OBJECT(s));
          if (CHARDEV_IS_MUX(s)) {
              MuxChardev *d = MUX_CHARDEV(s);

@@ -241,6 +242,7 @@ void qemu_chr_fe_deinit(CharBackend *b, bool del)
              } else {
                  object_unref(obj);
              }
+            object_unref(obj);
          }
          b->chr = NULL;
      }

to keep the chardev live between qemu_chr_cleanup() and monitor_cleanup().

Paolo