from threading import Thread
import difflib
for x in range(100):
    Thread(target=difflib._test, args=()).start()

Thread 92 "python" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffeca7e4640 (LWP 631239)]
0x00007ffff7d3f743 in unlink_chunk (p=p@entry=0x555555f56c00, av=0x7ffff7eb8c80 <main_arena>) at ./malloc/malloc.c:1634
1634    ./malloc/malloc.c: No such file or directory.
(gdb) bt
#0  0x00007ffff7d3f743 in unlink_chunk (p=p@entry=0x555555f56c00, av=0x7ffff7eb8c80 <main_arena>)
    at ./malloc/malloc.c:1634
#1  0x00007ffff7d40d2b in _int_free (av=0x7ffff7eb8c80 <main_arena>, p=0x555555f528a0,
    have_lock=<optimized out>) at ./malloc/malloc.c:4616
#2  0x00007ffff7d43453 in __GI___libc_free (mem=<optimized out>) at ./malloc/malloc.c:3391
#3  0x000055555570ed2c in _PyMem_RawFree (_unused_ctx=<optimized out>, ptr=<optimized out>)
    at Objects/obmalloc.c:90
#4  0x0000555555713955 in _PyMem_DebugRawFree (ctx=0x555555cdb8f8 <_PyRuntime+824>, p=0x555555f528c0)
    at Objects/obmalloc.c:2767
#5  0x000055555572c462 in PyMem_RawFree (ptr=ptr@entry=0x555555f528c0) at Objects/obmalloc.c:971
#6  0x00005555559527fc in free_threadstate (tstate=tstate@entry=0x555555f528c0) at Python/pystate.c:1411
#7  0x00005555559549c0 in _PyThreadState_DeleteCurrent (tstate=tstate@entry=0x555555f528c0)
    at Python/pystate.c:1834
#8  0x0000555555a11b74 in thread_run (boot_raw=boot_raw@entry=0x555555f52870)
    at ./Modules/_threadmodule.c:355
#9  0x0000555555974fdb in pythread_wrapper (arg=<optimized out>) at Python/thread_pthread.h:242
#10 0x00007ffff7d32ac3 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:442
#11 0x00007ffff7dc4850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

Thread 78 "python" received signal SIGABRT, Aborted.
[Switching to Thread 0x7ffed17f2640 (LWP 633651)]
__pthread_kill_implementation (no_tid=0, signo=6, threadid=140732413191744) at ./nptl/pthread_kill.c:44
44      ./nptl/pthread_kill.c: No such file or directory.
(gdb) bt
#0  __pthread_kill_implementation (no_tid=0, signo=6, threadid=140732413191744) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=140732413191744) at ./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=140732413191744, signo=signo@entry=6) at ./nptl/pthread_kill.c:89
#3  0x00007ffff7ce0476 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#4  0x00007ffff7cc67f3 in __GI_abort () at ./stdlib/abort.c:79
#5  0x00007ffff7d27676 in __libc_message (action=action@entry=do_abort,
    fmt=fmt@entry=0x7ffff7e79b77 "%s\n") at ../sysdeps/posix/libc_fatal.c:155
#6  0x00007ffff7d3ecfc in malloc_printerr (
    str=str@entry=0x7ffff7e7c6c0 "free(): unaligned chunk detected in tcache 2") at ./malloc/malloc.c:5664
#7  0x00007ffff7d40e3f in _int_free (av=0x7ffff7eb8c80 <main_arena>, p=0x555555dc79b0, have_lock=0)
    at ./malloc/malloc.c:4471
#8  0x00007ffff7d43453 in __GI___libc_free (mem=<optimized out>) at ./malloc/malloc.c:3391
#9  0x00007ffff41d4a2b in readline_set_completer_delims (module=<optimized out>, string=<optimized out>)
    at ./Modules/readline.c:593
#10 0x00005555557021ef in cfunction_vectorcall_O (
    func=<built-in method set_completer_delims of module object at remote 0x2000297b920>,
    args=<optimized out>, nargsf=<optimized out>, kwnames=<optimized out>) at Objects/methodobject.c:523
#11 0x000055555567cc55 in _PyObject_VectorcallTstate (tstate=0x555555f15bc0,
    callable=<built-in method set_completer_delims of module object at remote 0x2000297b920>,
    args=0x7ffed17f15a8, nargsf=9223372036854775809, kwnames=0x0) at ./Include/internal/pycore_call.h:167
#12 0x000055555567cd74 in PyObject_Vectorcall (
    callable=callable@entry=<built-in method set_completer_delims of module object at remote 0x2000297b920>,
 args=args@entry=0x7ffed17f15a8, nargsf=<optimized out>, kwnames=kwnames@entry=0x0) at Objects/call.c:327
#13 0x00005555558441f7 in _PyEval_EvalFrameDefault (tstate=tstate@entry=0x555555f15bc0,
    frame=<optimized out>, throwflag=throwflag@entry=0) at Python/generated_cases.c.h:955
#14 0x0000555555872978 in _PyEval_EvalFrame (throwflag=0, frame=<optimized out>, tstate=0x555555f15bc0)
    at ./Include/internal/pycore_ceval.h:116

Thread 43 "python" received signal SIGABRT, Aborted.
[Switching to Thread 0x7fff54ff9640 (LWP 636245)]
__pthread_kill_implementation (no_tid=0, signo=6, threadid=140734619424320) at ./nptl/pthread_kill.c:44
44      ./nptl/pthread_kill.c: No such file or directory.
(gdb) bt
#0  __pthread_kill_implementation (no_tid=0, signo=6, threadid=140734619424320) at ./nptl/pthread_kill.c:44
#1  __pthread_kill_internal (signo=6, threadid=140734619424320) at ./nptl/pthread_kill.c:78
#2  __GI___pthread_kill (threadid=140734619424320, signo=signo@entry=6) at ./nptl/pthread_kill.c:89
#3  0x00007ffff7ce0476 in __GI_raise (sig=sig@entry=6) at ../sysdeps/posix/raise.c:26
#4  0x00007ffff7cc67f3 in __GI_abort () at ./stdlib/abort.c:79
#5  0x00007ffff7d27676 in __libc_message (action=action@entry=do_abort,
    fmt=fmt@entry=0x7ffff7e79b77 "%s\n") at ../sysdeps/posix/libc_fatal.c:155
#6  0x00007ffff7d3ecfc in malloc_printerr (
    str=str@entry=0x7ffff7e7cf20 "tcache_thread_shutdown(): unaligned tcache chunk detected")
    at ./malloc/malloc.c:5664
#7  0x00007ffff7d436c4 in tcache_thread_shutdown () at ./malloc/malloc.c:3224
#8  __malloc_arena_thread_freeres () at ./malloc/arena.c:1003
#9  0x00007ffff7d461ca in __libc_thread_freeres () at ./malloc/thread-freeres.c:44
#10 0x00007ffff7d3294f in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:456
#11 0x00007ffff7dc4850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81