(gdb) backtrace
#0  0x4010448c in _System_state_Set (the_source=<value optimized out>, is_internal=<value optimized out>, the_error=<value optimized out>)
    at ../../cpukit/../../../milkymist/lib/include/rtems/score/sysstate.inl:37
#1  _Internal_error_Occurred (the_source=<value optimized out>, is_internal=<value optimized out>, the_error=<value optimized out>)
    at ../../../../../../rtems/c/src/../../cpukit/score/src/interr.c:58
#2  0x401022d0 in rtems_semaphore_obtain (id=436273162, option_set=0, timeout=0) at ../../../../../../rtems/c/src/../../cpukit/rtems/src/semobtain.c:82
#3  0x400e6368 in rtems_termios_ioctl (arg=0x408ed398) at ../../../../../../rtems/c/src/../../cpukit/libcsupport/src/termios.c:521
#4  0x400d887c in console_control (major=<value optimized out>, minor=<value optimized out>, arg=<value optimized out>)
    at ../../../../../../../../rtems/c/src/lib/libbsp/lm32/milkymist/../../lm32/shared/milkymist_console/console.c:219
#5  0x40102d24 in rtems_io_control (major=<value optimized out>, minor=<value optimized out>, argument=<value optimized out>)
    at ../../../../../../rtems/c/src/../../cpukit/sapi/src/iocontrol.c:47
#6  0x40147d9c in device_ioctl (iop=<value optimized out>, command=<value optimized out>, buffer=<value optimized out>)
    at ../../../../../../rtems/c/src/../../cpukit/libfs/src/imfs/deviceio.c:186
#7  0x400e3be4 in ioctl (fd=<value optimized out>, command=1099801888) at ../../../../../../rtems/c/src/../../cpukit/libcsupport/src/ioctl.c:50
#8  0x4012858c in tcgetattr (fd=<value optimized out>, tp=<value optimized out>)
    at ../../../../../../rtems/c/src/../../cpukit/libcsupport/src/tcgetattr.c:34
#9  0x401138a0 in rtems_shell_main_loop (shell_env_arg=0x418da520) at ../../../../../../rtems/c/src/../../cpukit/libmisc/shell/shell.c:655
#10 0x4011449c in rtems_shell_task (task_argument=<value optimized out>) at ../../../../../../rtems/c/src/../../cpukit/libmisc/shell/shell.c:557
#11 0x4014cb14 in _Thread_Handler () at ../../../../../../rtems/c/src/../../cpukit/score/src/threadhandler.c:157
#12 0x4014ca88 in _Heap_Get_information (the_heap=<value optimized out>, the_info=0x5)
    at ../../../../../../rtems/c/src/../../cpukit/score/src/heapgetinfo.c:57