Get the PID ps -Af | grep ruby
Attach to the process sudo gdb -p PID
Enter in Python python
Run snippet gdb_ruby_backtrace.py
Execute python get_ruby_stacktrace() to get backtrace
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Debug and getting a backtrace of stuck Ruby process with gdb
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| # Updated for Ruby 2.3 | |
| string_t = None | |
| def get_rstring(addr): | |
| s = addr.cast(string_t.pointer()) | |
| if s['basic']['flags'] & (1 << 13): | |
| return s['as']['heap']['ptr'].string() | |
| else: | |
| return s['as']['ary'].string() | |
| def get_lineno(iseq, pos): | |
| if pos != 0: | |
| pos -= 1 | |
| t = iseq['line_info_table'] | |
| t_size = iseq['line_info_size'] | |
| if t_size == 0: | |
| return 0 | |
| elif t_size == 1: | |
| return t[0]['line_no'] | |
| for i in range(0, int(t_size)): | |
| if pos == t[i]['position']: | |
| return t[i]['line_no'] | |
| elif t[i]['position'] > pos: | |
| return t[i-1]['line_no'] | |
| return t[t_size-1]['line_no'] | |
| def get_ruby_stacktrace(th=None): | |
| global string_t | |
| try: | |
| control_frame_t = gdb.lookup_type('rb_control_frame_t') | |
| string_t = gdb.lookup_type('struct RString') | |
| except gdb.error: | |
| raise gdb.GdbError ("ruby extension requires symbols") | |
| if th == None: | |
| th = gdb.parse_and_eval('ruby_current_thread') | |
| else: | |
| th = gdb.parse_and_eval('(rb_thread_t *) %s' % th) | |
| last_cfp = th['cfp'] | |
| start_cfp = (th['stack'] + th['stack_size']).cast(control_frame_t.pointer()) - 2 | |
| size = start_cfp - last_cfp + 1 | |
| cfp = start_cfp | |
| call_stack = [] | |
| for i in range(0, int(size)): | |
| if cfp['iseq'].dereference().address != 0: | |
| if cfp['pc'].dereference().address != 0: | |
| s = "{}:{}:in `{}'".format(get_rstring(cfp['iseq']['body']['location']['path']), | |
| get_lineno(cfp['iseq']['body'], cfp['pc'] - cfp['iseq']['body']['iseq_encoded']), | |
| get_rstring(cfp['iseq']['body']['location']['label'])) | |
| call_stack.append(s) | |
| cfp -= 1 | |
| for i in reversed(call_stack): | |
| print(i) | |
| end |
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