System hangs when mailbox interrupt is enabled about oh HOT 1 CLOSED

# /usr/epiphany/bin/mailbox
InitialEpiphany(): rows,cols: ( 4, 4)
main(): devfd 6, epollfd 5, kernelEventfd 7, cancelfd 8
RunTest():   0: Message from eCore 0x808 ( 0, 0): "Hello World from core 0x808!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=00000808 HI=810f0320
RunTest():   1: Message from eCore 0x809 ( 0, 1): "Hello World from core 0x809!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=00000809 HI=810f0320
RunTest():   2: Message from eCore 0x80a ( 0, 2): "Hello World from core 0x80a!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=0000080a HI=810f0320
RunTest():   3: Message from eCore 0x80b ( 0, 3): "Hello World from core 0x80b!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=0000080b HI=810f0320
RunTest():   4: Message from eCore 0x848 ( 1, 0): "Hello World from core 0x848!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=00000848 HI=810f0320
RunTest():   5: Message from eCore 0x849 ( 1, 1): "Hello World from core 0x849!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=00000849 HI=810f0320
RunTest():   6: Message from eCore 0x84a ( 1, 2): "Hello World from core 0x84a!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=0000084a HI=810f0320
RunTest():   7: Message from eCore 0x84b ( 1, 3): "Hello World from core 0x84b!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=0000084b HI=810f0320
RunTest():   8: Message from eCore 0x888 ( 2, 0): "Hello World from core 0x888!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=00000888 HI=810f0320
RunTest():   9: Message from eCore 0x889 ( 2, 1): "Hello World from core 0x889!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=00000889 HI=810f0320
RunTest():  10: Message from eCore 0x88a ( 2, 2): "Hello World from core 0x88a!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=0000088a HI=810f0320
RunTest():  11: Message from eCore 0x88b ( 2, 3): "Hello World from core 0x88b!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=0000088b HI=810f0320
RunTest():  12: Message from eCore 0x8c8 ( 3, 0): "Hello World from core 0x8c8!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=000008c8 HI=810f0320
RunTest():  13: Message from eCore 0x8c9 ( 3, 1): "Hello World from core 0x8c9!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=000008c9 HI=810f0320
RunTest():  14: Message from eCore 0x8ca ( 3, 2): "Hello World from core 0x8ca!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=000008ca HI=810f0320
RunTest():  15: Message from eCore 0x8cb ( 3, 3): "Hello World from core 0x8cb!"
main(): PRE_STAT=00000001 POST_STAT=00000000 LO=000008cb HI=810f0320
main(): wait for SleepThenCancel thread to terminate