Comment # 13 on bug 1139967 from Martin Vidner

Running the UI without threads, like this, makes the problem go away.

ruby -ryast -e 'module Yast; self.ui_component="qt"; ui_create("qt",
["--nothreads"]); import "UI"; UI.OpenDialog(Term.new(:PushButton,
Term.new(:id, :myid), "HI")); loop { sleep 0.3; ui = UI.PollInput; p ui; break
if ui == :myid }; end'

(In reply to Ladislav Slez�k from comment #11)
> The last line reported by strace before getting stuck is:
> futex(0x561fd6a171e8, FUTEX_WAIT_PRIVATE, 0, NULL
> So it might be kernel related...

futex is just a synchronization primitive. ltrace might be better here.