# triggering program
# based on test.test_faulthandler.FaultHandlerTests.test_dump_traceback_threads
import faulthandler
from threading import Thread, Event
class Waiter(Thread):
def __init__(self):
Thread.__init__(self)
self.running = Event()
self.stop = Event()
def run(self):
self.running.set()
self.stop.wait()
def main():
for i in range(100):
waiter = Waiter()
waiter.start()
waiter.running.wait()
faulthandler.dump_traceback(all_threads=True)
waiter.stop.set()
waiter.join()
if __name__ == '__main__':
main()Thread 1 "python" received signal SIGSEGV, Segmentation fault.
_PyFrame_GetCode (f=f@entry=0x7ffff7fb32d8) at ./Include/internal/pycore_frame.h:83
83 assert(PyCode_Check(executable));
(gdb) p executable
$7 = 0x0
(gdb) bt
#0 _PyFrame_GetCode (f=f@entry=0x7ffff7fb32d8) at ./Include/internal/pycore_frame.h:83
#1 PyUnstable_InterpreterFrame_GetLine (frame=frame@entry=0x7ffff7fb32d8) at Python/frame.c:149
#2 0x000055555590e9eb in dump_frame (fd=2, frame=0x7ffff7fb32d8) at Python/traceback.c:905
#3 dump_traceback (fd=fd@entry=2, tstate=tstate@entry=0x555555cef140, write_header=write_header@entry=0) at Python/traceback.c:974
#4 0x000055555590ed1c in _Py_DumpTracebackThreads (fd=2, interp=<optimized out>, interp@entry=0x0, current_tstate=0x555555c5dea8 <_PyRuntime+359528>) at Python/traceback.c:1090
#5 0x0000555555924489 in faulthandler_dump_traceback_py (self=<optimized out>, args=<optimized out>, kwargs=<optimized out>) at ./Modules/faulthandler.c:240
#6 0x00005555556feae1 in cfunction_call (func=func@entry=<built-in method dump_traceback of module object at remote 0x20000778900>, args=args@entry=(), kwargs=kwargs@entry={'all_threads': True})
[...]
Python 3.14.0a0 experimental free-threading build (bisect/bad:b2afe2aae48, Jan 1 2025, 17:09:16) [Clang 19.1.6 (++20241217105838+657e03f8625c-1exp120241217105944.74)]
Crash report
What happened?
This will case the interpreter to segfault if built with
--disable-gil --with-pydebug. I've bisected it to this commit:b2afe2a: gh-123924
Using gdb:
CPython versions tested on:
CPython main branch
Operating systems tested on:
Linux
Output from running 'python -VV' on the command line:
Python 3.14.0a0 experimental free-threading build (bisect/bad:b2afe2aae48, Jan 1 2025, 17:09:16) [Clang 19.1.6 (++20241217105838+657e03f8625c-1
exp120241217105944.74)]Linked PRs
faulthandler#128422faulthandler(GH-128422) #128423faulthandlerif the GIL is disabled #128425Py_FatalErroron the free-threaded build #128758