Problem with iotest 233

[Thomas Huth <thuth@redhat.com>]

  Hi!

I'm facing a weird hang in iotest 233 on my Fedora 41 laptop. When running

  ./check -raw 233

the test simply hangs. Looking at the log, the last message is "== check 
plain client to TLS server fails ==". I added some debug messages, and it 
seems like the previous NBD server is not correctly terminated here.
The test works fine again if I apply this patch:

diff --git a/tests/qemu-iotests/common.nbd b/tests/qemu-iotests/common.nbd
--- a/tests/qemu-iotests/common.nbd
+++ b/tests/qemu-iotests/common.nbd
@@ -35,7 +35,7 @@ nbd_server_stop()
          read NBD_PID < "$nbd_pid_file"
          rm -f "$nbd_pid_file"
          if [ -n "$NBD_PID" ]; then
-            kill "$NBD_PID"
+            kill -9 "$NBD_PID"
          fi
      fi
      rm -f "$nbd_unix_socket" "$nbd_stderr_fifo"

... but that does not look like the right solution to me. What could prevent 
the qemu-nbd from correctly shutting down when it receives a normal SIGTERM 
signal?

  Thomas