$ ./ruby --disable=gems mutex_bug.rb
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:35 set_trace_func   Kernel  0
 #<Thread:0x007fea210c0298>     line mutex_bug.rb:53                      0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:41      times  Integer  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:41      times  Integer  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:41        map Enumerable  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:41       each Enumerator  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:41      times  Integer  0
 #<Thread:0x007fea210c0298>     line mutex_bug.rb:42                      0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:42        new   Thread  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:42 initialize   Thread  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:42 initialize   Thread  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:42        new   Thread  0
 #<Thread:0x007fea210c0298>     line mutex_bug.rb:42                      0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:43                      0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:42        new   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:43      times  Integer  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:42 initialize   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                      0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:42 initialize   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:43                      0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:43      times  Integer  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:42        new   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:41      times  Integer  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                      0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:45                      0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:41       each Enumerator  0
 #<Thread:0x007fea210a3f58>     call mutex_bug.rb:26      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                      0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:41        map Enumerable  0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:27      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53    to_proc   Symbol  0
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor  0
 #<Thread:0x007fea210a3f58>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:45                      0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor  0
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53    to_proc   Symbol  0
 #<Thread:0x007fea210a2428>     call mutex_bug.rb:26      stuff MyMonitor  0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53       each    Array  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:27      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread  0
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53       join   Thread  0
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea210a2428>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                      0
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor  0
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor  0
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a3f58> 0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea210a3f58> 0
 #<Thread:0x007fea210a3f58>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a3f58> 1
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a3f58> 0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a3f58> 0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a3f58>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a3f58>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a3f58>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a3f58>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a2428> 0
 #<Thread:0x007fea210a2428>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a2428> 1
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a2428> 0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a2428> 0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a2428>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a2428>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a2428>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210a2428>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a3f58> c-return mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:45                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2107b558>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2107b558>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0  #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:11    current   Thread  0

 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a2428> c-return mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                      0
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread  0
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea2107b558> 0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea2107b558> 0
 #<Thread:0x007fea2107b558>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                     #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:45                     #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210701f8>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210701f8>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea2107b558> 0
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2107b558> 0
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea2107b558> 0
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2107b558> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2107b558> 1
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea2107b558>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea2107b558>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea2107b558>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea2107b558>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea2107b558> c-return mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210701f8>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                     #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210701f8> 1  #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:45                     #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea210701f8> 1

 #<Thread:0x007fea210701f8>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210701f8> 1  #<Thread:0x007fea21058558>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210701f8> 1

 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea21058558>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210701f8> 1
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea21058558>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea210701f8> 0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210701f8>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210701f8>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210701f8>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210701f8>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210701f8> c-return mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea21058558>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                      0
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread  0
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread  0
 #<Thread:0x007fea21058558>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21058558> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                     #<Thread:0x007fea21058558> 0
 #<Thread:0x007fea21058558>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:45                     #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21058558> 1
 #<Thread:0x007fea21058558>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea21058558> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21058558> 0
 #<Thread:0x007fea21058558>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea21058558> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21058558> 0
 #<Thread:0x007fea21058558>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21058558> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21058558>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21058558>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea21058558>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea21058558>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21041a88> 0  #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread #<Thread:0x007fea21041a88> 0

 #<Thread:0x007fea21058558> c-return mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea21041a88> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                     #<Thread:0x007fea21041a88> 0
 #<Thread:0x007fea21041a88>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:45                     #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea21041a88> 1  #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21041a88> 1

 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21041a88> 1
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea21041a88> 0  #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21041a88> 0

 #<Thread:0x007fea21041a88>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea21041a88> 0
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21041a88>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea21041a88>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21041a88>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea21041a88>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                      0
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21041a88> c-return mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread  0
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread  0
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                      0
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread  0
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21029d70> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21029d70> 0
 #<Thread:0x007fea21029d70>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea2107bbe8>     line mutex_bug.rb:45                     #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea2107bbe8>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21029d70> 1
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea21029d70> 0
 #<Thread:0x007fea2107bbe8>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21029d70> 0
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea21029d70> 0
 #<Thread:0x007fea2107bbe8>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21029d70> 0
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea2107bbe8>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:22     unlock    Mutex  0  #<Thread:0x007fea2107bbe8>   c-call mutex_bug.rb:11    current   Thread  0

 #<Thread:0x007fea2107bbe8> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea2107bbe8>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea21029d70>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea21029d70>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea2107bbe8>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21029d70>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea21029d70>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                     #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea21029d70> c-return mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:45                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2103b750>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea2103b750>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2107bbe8> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea2107bbe8>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea2107bbe8>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea2107bbe8> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2107bbe8>   return mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                     #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2107bbe8>   return mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:13  mon_enter MyMonitor #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                     #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:13    current   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:13    current   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2107bbe8> 0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea2103b750> 0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2103b750> 0
 #<Thread:0x007fea2103b750>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:45                     #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2103b750> 1
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea2103b750> 0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2103b750> 0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea2103b750> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2103b750> 0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2103b750>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea2103b750>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea2103b750>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea2103b750>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0  #<Thread:0x007fea2102bc60>     line mutex_bug.rb:13  mon_enter MyMonitor  0

 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea2103b750> c-return mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                      0
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea2102bc60> 0
 #<Thread:0x007fea2102bc60>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:45                     #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea2102bc60> 1  #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 1

 #<Thread:0x007fea21083578>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 1  #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 1

 #<Thread:0x007fea2102bc60>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 1
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea2102bc60> 0  #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2102bc60> 1

 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea2102bc60> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2102bc60> 0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea2102bc60> 0
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea2102bc60> 0
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2102bc60>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea2102bc60>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea2102bc60>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea2102bc60>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea21083578>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea2102bc60> c-return mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea21083578>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                     #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea21083578>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                     #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21083578> 1  #<Thread:0x007fea21083578> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:45                     #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21083578> 1

 #<Thread:0x007fea2104be98>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea2104be98>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21083578> 1
 #<Thread:0x007fea21083578>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea21083578>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21083578> 0
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:22     unlock    Mutex  0  #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread  0

 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea21083578>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea21083578>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea21083578>     line mutex_bug.rb:46                     #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea21083578>   c-call mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0  #<Thread:0x007fea2104be98> c-return mutex_bug.rb:12       lock    Mutex  0

 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea21083578> c-return mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                      0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea2104be98>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:45                     #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2104be98> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea2104be98> 0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea2104be98>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea2104be98>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea2104be98>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea2104be98>   c-call mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21088ca8> 0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread #<Thread:0x007fea21088ca8> 0  #<Thread:0x007fea21088ca8>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea2104be98> c-return mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea21088ca8> 1

 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                     #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                     #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea21088ca8> 1  #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21088ca8> 1

 #<Thread:0x007fea21098c70>     line mutex_bug.rb:45                     #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21098c70>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea21088ca8> 0
 #<Thread:0x007fea21098c70>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21088ca8> 1
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea21088ca8> 0
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21088ca8> 0
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea21098c70>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21088ca8> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor  0
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea21088ca8>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea21098c70>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea21088ca8>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea21098c70>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea21098c70> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea21088ca8>     line mutex_bug.rb:46                      0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea21088ca8>   c-call mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea21098c70>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea21098c70>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210aa010> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210aa010> 0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210aa010>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea21088ca8> c-return mutex_bug.rb:46      sleep   Kernel  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:49       kill   Thread  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:50                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:44                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea21061450>     line mutex_bug.rb:45                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea21061450>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea21061450>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:48                     #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea21061450>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 1
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea210a8fd0> 0  #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:21   mon_exit MyMonitor #<Thread:0x007fea210a8fd0> 0

 #<Thread:0x007fea21061450>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea210a8fd0> 0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:22   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>     call mutex_bug.rb:10  mon_enter MyMonitor  0
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea21061450> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea21061450>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:11  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21098c70> c-return mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea21098c70>     line mutex_bug.rb:13  mon_enter MyMonitor  0
 #<Thread:0x007fea210aa010> c-return mutex_bug.rb:11    current   Thread  0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:22     unlock    Mutex  0
 #<Thread:0x007fea21098c70>   c-call mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210aa010>     line mutex_bug.rb:12  mon_enter MyMonitor  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:24   mon_exit MyMonitor  0
 #<Thread:0x007fea210aa010>   c-call mutex_bug.rb:12       lock    Mutex  0
 #<Thread:0x007fea210a8fd0>   return mutex_bug.rb:30      stuff MyMonitor  0
 #<Thread:0x007fea21098c70> c-return mutex_bug.rb:13    current   Thread  0
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:49                      0
 #<Thread:0x007fea21098c70>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21098c70> 0
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:49       kill   Thread #<Thread:0x007fea21098c70> 0
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:49       kill   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21098c70>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:50                     #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21098c70>   return mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21098c70> 1  #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:50       join   Thread #<Thread:0x007fea21098c70> 1

 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:50       join   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:44                     #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44        new   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44 initialize   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21061450> c-return mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21061450>     line mutex_bug.rb:13  mon_enter MyMonitor #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:44        new   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:13    current   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21031e58>     line mutex_bug.rb:45                     #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:48                     #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21061450> c-return mutex_bug.rb:13    current   Thread #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21031e58>     call mutex_bug.rb:26      stuff MyMonitor #<Thread:0x007fea21098c70> 1
 #<Thread:0x007fea21061450>     line mutex_bug.rb:15  mon_enter MyMonitor #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea21061450>   return mutex_bug.rb:16  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea210a8fd0>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58>     line mutex_bug.rb:27      stuff MyMonitor #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58>     call mutex_bug.rb:10  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>     line mutex_bug.rb:28      stuff MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58>     line mutex_bug.rb:11  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58>   c-call mutex_bug.rb:11    current   Thread #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea210a8fd0> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58> c-return mutex_bug.rb:11    current   Thread #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea210a8fd0>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58>     line mutex_bug.rb:12  mon_enter MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea210a8fd0>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:28      write       IO #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21031e58>   c-call mutex_bug.rb:12       lock    Mutex #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450> c-return mutex_bug.rb:28       to_s NilClass #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450> c-return mutex_bug.rb:28      write       IO #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450> c-return mutex_bug.rb:28      print   Kernel #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>     line mutex_bug.rb:29      stuff MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>     call mutex_bug.rb:18   mon_exit MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>     line mutex_bug.rb:19   mon_exit MyMonitor #<Thread:0x007fea21061450> 2
 #<Thread:0x007fea21061450>     line mutex_bug.rb:20   mon_exit MyMonitor #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea21061450>   return mutex_bug.rb:24   mon_exit MyMonitor #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea21061450>   return mutex_bug.rb:30      stuff MyMonitor #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea21061450>     line mutex_bug.rb:46                     #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea21061450>   c-call mutex_bug.rb:46      sleep   Kernel #<Thread:0x007fea21061450> 1
^C #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53        new    Class #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53 initialize Interrupt #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53 initialize SignalException #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53 initialize Exception #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53 initialize Exception #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53 initialize SignalException #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53 initialize Interrupt #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53        new    Class #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53  exception Exception #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53  exception Exception #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298>   c-call mutex_bug.rb:53  backtrace Exception #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53  backtrace Exception #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298>    raise mutex_bug.rb:53       join   Thread #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53       join   Thread #<Thread:0x007fea21061450> 1
 #<Thread:0x007fea210c0298> c-return mutex_bug.rb:53       each    Array #<Thread:0x007fea21061450> 1
mutex_bug.rb:53:in `join': Interrupt
  from mutex_bug.rb:53:in `each'
  from mutex_bug.rb:53:in `<main>'