As of 38b3237bd6 (shortly after 1.4.1), the tests/foreign.scm test occasionally hangs on x86_64-linux-gnu (epoll backend):
assert #f equal to #f: ok
assert #t terminates: ok
WARNING: (tests foreign): `sleep' imported from both (fibers) and (fibers timers)
assert (sleep 1) terminates: ok
assert (perform-operation (sleep-operation 1)) terminates: ok
assert (receive-from-fiber 42) equal to 42: ^Z
Backtraces:
(gdb) info threads
Id Target Id Frame
1 Thread 0x7f87b6c19740 (LWP 648) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
2 Thread 0x7f87b29526c0 (LWP 654) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
3 Thread 0x7f87b33846c0 (LWP 653) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
* 4 Thread 0x7f87b47d46c0 (LWP 652) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
5 Thread 0x7f87b52686c0 (LWP 651) "GC-marker-2" 0x00007f87b6cab7a7 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
6 Thread 0x7f87b5bf86c0 (LWP 650) "GC-marker-1" 0x00007f87b6cab7a7 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
7 Thread 0x7f87b65886c0 (LWP 649) "GC-marker-0" 0x00007f87b6cab7a7 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
(gdb) thread apply all bt
[skipping GC marker thread and thread 4, the finalization thread]
Thread 3 (Thread 0x7f87b33846c0 (LWP 653) "guile"):
#0 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#1 0x00007f87b6cab788 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#2 0x00007f87b6cab7cd in __syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#3 0x00007f87b6d299ed in epoll_wait () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#4 0x00007f87b3d47335 in do_epoll_wait (p=0x7f87b33836f0) at extensions/epoll.c:134
#5 0x00007f87b7167871 in ?? () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#6 0x00007f87b71694ac in ?? () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#7 0x00007f87b71741dc in GC_do_blocking () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#8 0x00007f87b728dfc5 in scm_without_guile (func=0x7f87b3d47320 <do_epoll_wait>, data=0x7f87b33836f0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:710
#9 0x00007f87b3d4759d in scm_primitive_epoll_wait (epfd=<optimized out>, wakefd=<optimized out>, wokefd=<optimized out>, eventsv=<optimized out>, timeout=<optimized out>) at extensions/epoll.c:178
#10 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977900) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#11 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b348fe60, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#12 0x00007f87b720d678 in scm_call_with_unblocked_asyncs (proc=0x7f87b348fe60) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/async.c:406
#13 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977900) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#14 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b346db90, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#15 0x00007f87b7293093 in really_launch (d=0x7f87b34712c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:782
#16 0x00007f87b720fc3a in c_body (d=0x7f87b3383e00) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:430
#17 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977900) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#18 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a17600, argv=<optimized out>, nargs=2) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#19 0x00007f87b721132a in scm_call_2 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:503
#20 0x00007f87b72bacd4 in scm_c_with_exception_handler.constprop.0 (type=0x404, handler_data=handler_data@entry=0x7f87b3383d90, thunk_data=thunk_data@entry=0x7f87b3383d90, thunk=<optimized out>, handler=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/exceptions.c:170
#21 0x00007f87b7293daf in scm_c_catch (tag=<optimized out>, body=<optimized out>, body_data=<optimized out>, handler=<optimized out>, handler_data=<optimized out>, pre_unwind_handler=<optimized out>, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/throw.c:168
#22 0x00007f87b72120b6 in scm_i_with_continuation_barrier (pre_unwind_handler=0x7f87b7211df0 <pre_unwind_handler>, body=0x7f87b720fc30 <c_body>, body_data=0x7f87b3383e00, handler=0x7f87b72187e0 <c_handler>, handler_data=0x7f87b3383e00, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:368
#23 scm_c_with_continuation_barrier (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:464
#24 0x00007f87b729300a in with_guile (base=0x7f87b3383e88, data=0x7f87b3383eb0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:649
#25 0x00007f87b7174198 in GC_call_with_stack_base () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#26 0x00007f87b728d22d in scm_i_with_guile (func=0x7f87b7293020 <really_launch>, data=0x7f87b34712c0, dynamic_state=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:692
#27 launch_thread (d=0x7f87b34712c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:791
#28 0x00007f87b6caeaed in start_thread () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#29 0x00007f87b6d29768 in __clone3 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
Thread 2 (Thread 0x7f87b29526c0 (LWP 654) "guile"):
#0 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#1 0x00007f87b6cab788 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#2 0x00007f87b6cabd9c in __futex_abstimed_wait_common () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#3 0x00007f87b6cae1b8 in pthread_cond_wait@@GLIBC_2.3.2 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#4 0x00007f87b728e0f5 in scm_pthread_cond_wait (cond=<optimized out>, mutex=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1610
#5 0x00007f87b7290f9b in block_self (queue=0x7f87b6a74c40, mutex=mutex@entry=0x7f87b6a76fc0, waittime=waittime@entry=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:313
#6 0x00007f87b729393f in lock_mutex (kind=SCM_MUTEX_RECURSIVE, m=0x7f87b6a76fc0, current_thread=0x7f87b69776c0, waittime=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1025
#7 scm_timed_lock_mutex (mutex=0x7f87b6a74c30, timeout=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1090
#8 0x00007f87b67b07cf in ?? ()
#9 0x00007f87b69776c0 in ?? ()
#10 0x00007f87b485ad78 in ?? ()
#11 0x00007f87b69776c0 in ?? ()
#12 0x00007f87b724264b in scm_jit_enter_mcode (thread=0x7f87b69776c0, mcode=0x7f87b67a2100 "I211円314円I)304円I203円374円020円017円214円`002円") at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/jit.c:6061
#13 0x00007f87b72991b0 in vm_regular_engine (thread=0x7f87b485ad58) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:360
#14 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a24380, argv=<optimized out>, nargs=3) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#15 0x00007f87b721138f in scm_call_3 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>, arg3=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:510
#16 0x00007f87b723b600 in resolve_module (name=name@entry=0x7f87b48af420, public_p=public_p@entry=1 '001円') at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/intrinsics.c:320
#17 0x00007f87b723bec5 in resolve_module (name=0x7f87b48af420, public_p=1 '001円') at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/intrinsics.c:380
#18 lookup_bound_public (module=0x7f87b48af420, name=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/intrinsics.c:378
#19 0x00007f87b7299118 in vm_regular_engine (thread=0x7f87b69776c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:3474
#20 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b34a9f40, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#21 0x00007f87b720d678 in scm_call_with_unblocked_asyncs (proc=0x7f87b34a9f40) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/async.c:406
#22 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b69776c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#23 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b346d3c0, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#24 0x00007f87b7293093 in really_launch (d=0x7f87b3494780) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:782
#25 0x00007f87b720fc3a in c_body (d=0x7f87b2951e00) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:430
#26 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b69776c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#27 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a17600, argv=<optimized out>, nargs=2) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#28 0x00007f87b721132a in scm_call_2 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:503
#29 0x00007f87b72bacd4 in scm_c_with_exception_handler.constprop.0 (type=0x404, handler_data=handler_data@entry=0x7f87b2951d90, thunk_data=thunk_data@entry=0x7f87b2951d90, thunk=<optimized out>, handler=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/exceptions.c:170
#30 0x00007f87b7293daf in scm_c_catch (tag=<optimized out>, body=<optimized out>, body_data=<optimized out>, handler=<optimized out>, handler_data=<optimized out>, pre_unwind_handler=<optimized out>, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/throw.c:168
#31 0x00007f87b72120b6 in scm_i_with_continuation_barrier (pre_unwind_handler=0x7f87b7211df0 <pre_unwind_handler>, body=0x7f87b720fc30 <c_body>, body_data=0x7f87b2951e00, handler=0x7f87b72187e0 <c_handler>, handler_data=0x7f87b2951e00, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:368
#32 scm_c_with_continuation_barrier (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:464
#33 0x00007f87b729300a in with_guile (base=0x7f87b2951e88, data=0x7f87b2951eb0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:649
#34 0x00007f87b7174198 in GC_call_with_stack_base () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#35 0x00007f87b728d22d in scm_i_with_guile (func=0x7f87b7293020 <really_launch>, data=0x7f87b3494780, dynamic_state=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:692
#36 launch_thread (d=0x7f87b3494780) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:791
#37 0x00007f87b6caeaed in start_thread () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#38 0x00007f87b6d29768 in __clone3 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
Thread 1 (Thread 0x7f87b6c19740 (LWP 648) "guile"):
#0 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#1 0x00007f87b6cab788 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#2 0x00007f87b6cabd9c in __futex_abstimed_wait_common () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#3 0x00007f87b6cae1b8 in pthread_cond_wait@@GLIBC_2.3.2 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#4 0x00007f87b728e0f5 in scm_pthread_cond_wait (cond=<optimized out>, mutex=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1610
#5 0x00007f87b7290f9b in block_self (queue=0x7f87b34a6340, mutex=mutex@entry=0x7f87b34aefc0, waittime=waittime@entry=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:313
#6 0x00007f87b7293685 in timed_wait (kind=SCM_MUTEX_STANDARD, m=0x7f87b34aefc0, c=0x7f87b34abed0, current_thread=0x7f87b6977d80, waittime=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1336
#7 scm_timed_wait_condition_variable (cond=0x7f87b34a6350, mutex=0x7f87b34a6320, timeout=0x904) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1429
#8 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977d80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#9 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b695c030, argv=<optimized out>, nargs=1) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#10 0x00007f87b72116f7 in scm_primitive_eval (exp=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:671
#11 0x00007f87b7245c79 in scm_primitive_load (filename=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/load.c:131
#12 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977d80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#13 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b695c030, argv=<optimized out>, nargs=1) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#14 0x00007f87b72116f7 in scm_primitive_eval (exp=<optimized out>, exp@entry=0x7f87b6a98e40) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:671
#15 0x00007f87b72173e3 in scm_eval (exp=0x7f87b6a98e40, module_or_state=0x7f87b6a8cc80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:705
#16 0x00007f87b7275d00 in scm_shell (argc=4, argv=0x7ffdbfe33508) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/script.c:357
#17 0x00007f87b72286bc in invoke_main_func (body_data=0x7ffdbfe333a0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/init.c:312
#18 0x00007f87b720fc3a in c_body (d=0x7ffdbfe332c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:430
#19 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977d80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#20 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a17600, argv=<optimized out>, nargs=2) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#21 0x00007f87b721132a in scm_call_2 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:503
#22 0x00007f87b72bacd4 in scm_c_with_exception_handler.constprop.0 (type=0x404, handler_data=handler_data@entry=0x7ffdbfe33250, thunk_data=thunk_data@entry=0x7ffdbfe33250, thunk=<optimized out>, handler=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/exceptions.c:170
#23 0x00007f87b7293daf in scm_c_catch (tag=<optimized out>, body=<optimized out>, body_data=<optimized out>, handler=<optimized out>, handler_data=<optimized out>, pre_unwind_handler=<optimized out>, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/throw.c:168
#24 0x00007f87b72120b6 in scm_i_with_continuation_barrier (pre_unwind_handler=0x7f87b7211df0 <pre_unwind_handler>, body=0x7f87b720fc30 <c_body>, body_data=0x7ffdbfe332c0, handler=0x7f87b72187e0 <c_handler>, handler_data=0x7ffdbfe332c0, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:368
#25 scm_c_with_continuation_barrier (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:464
#26 0x00007f87b729300a in with_guile (base=0x7ffdbfe33348, data=0x7ffdbfe33370) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:649
#27 0x00007f87b7174198 in GC_call_with_stack_base () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#28 0x00007f87b728df68 in scm_i_with_guile (func=<optimized out>, data=<optimized out>, dynamic_state=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:692
#29 scm_with_guile (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:698
#30 0x00007f87b7231555 in scm_boot_guile (argc=argc@entry=4, argv=argv@entry=0x7ffdbfe33508, main_func=main_func@entry=0x401240 <inner_main>, closure=closure@entry=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/init.c:295
#31 0x00000000004010f6 in main (argc=4, argv=0x7ffdbfe33508) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/guile.c:94
Looks like thread 1 (which is not running Fibers) is stuck in wait-condition-variable (from suspend in perform-operation).
As of 38b3237bd6c2e634a1716462ea574276f7ea93e3 (shortly after 1.4.1), the `tests/foreign.scm` test occasionally hangs on x86_64-linux-gnu (epoll backend):
```
assert #f equal to #f: ok
assert #t terminates: ok
WARNING: (tests foreign): `sleep' imported from both (fibers) and (fibers timers)
assert (sleep 1) terminates: ok
assert (perform-operation (sleep-operation 1)) terminates: ok
assert (receive-from-fiber 42) equal to 42: ^Z
```
Backtraces:
```
(gdb) info threads
Id Target Id Frame
1 Thread 0x7f87b6c19740 (LWP 648) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
2 Thread 0x7f87b29526c0 (LWP 654) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
3 Thread 0x7f87b33846c0 (LWP 653) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
* 4 Thread 0x7f87b47d46c0 (LWP 652) "guile" 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
5 Thread 0x7f87b52686c0 (LWP 651) "GC-marker-2" 0x00007f87b6cab7a7 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
6 Thread 0x7f87b5bf86c0 (LWP 650) "GC-marker-1" 0x00007f87b6cab7a7 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
7 Thread 0x7f87b65886c0 (LWP 649) "GC-marker-0" 0x00007f87b6cab7a7 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
(gdb) thread apply all bt
[skipping GC marker thread and thread 4, the finalization thread]
Thread 3 (Thread 0x7f87b33846c0 (LWP 653) "guile"):
#0 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#1 0x00007f87b6cab788 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#2 0x00007f87b6cab7cd in __syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#3 0x00007f87b6d299ed in epoll_wait () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#4 0x00007f87b3d47335 in do_epoll_wait (p=0x7f87b33836f0) at extensions/epoll.c:134
#5 0x00007f87b7167871 in ?? () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#6 0x00007f87b71694ac in ?? () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#7 0x00007f87b71741dc in GC_do_blocking () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#8 0x00007f87b728dfc5 in scm_without_guile (func=0x7f87b3d47320 <do_epoll_wait>, data=0x7f87b33836f0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:710
#9 0x00007f87b3d4759d in scm_primitive_epoll_wait (epfd=<optimized out>, wakefd=<optimized out>, wokefd=<optimized out>, eventsv=<optimized out>, timeout=<optimized out>) at extensions/epoll.c:178
#10 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977900) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#11 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b348fe60, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#12 0x00007f87b720d678 in scm_call_with_unblocked_asyncs (proc=0x7f87b348fe60) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/async.c:406
#13 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977900) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#14 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b346db90, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#15 0x00007f87b7293093 in really_launch (d=0x7f87b34712c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:782
#16 0x00007f87b720fc3a in c_body (d=0x7f87b3383e00) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:430
#17 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977900) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#18 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a17600, argv=<optimized out>, nargs=2) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#19 0x00007f87b721132a in scm_call_2 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:503
#20 0x00007f87b72bacd4 in scm_c_with_exception_handler.constprop.0 (type=0x404, handler_data=handler_data@entry=0x7f87b3383d90, thunk_data=thunk_data@entry=0x7f87b3383d90, thunk=<optimized out>, handler=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/exceptions.c:170
#21 0x00007f87b7293daf in scm_c_catch (tag=<optimized out>, body=<optimized out>, body_data=<optimized out>, handler=<optimized out>, handler_data=<optimized out>, pre_unwind_handler=<optimized out>, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/throw.c:168
#22 0x00007f87b72120b6 in scm_i_with_continuation_barrier (pre_unwind_handler=0x7f87b7211df0 <pre_unwind_handler>, body=0x7f87b720fc30 <c_body>, body_data=0x7f87b3383e00, handler=0x7f87b72187e0 <c_handler>, handler_data=0x7f87b3383e00, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:368
#23 scm_c_with_continuation_barrier (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:464
#24 0x00007f87b729300a in with_guile (base=0x7f87b3383e88, data=0x7f87b3383eb0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:649
#25 0x00007f87b7174198 in GC_call_with_stack_base () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#26 0x00007f87b728d22d in scm_i_with_guile (func=0x7f87b7293020 <really_launch>, data=0x7f87b34712c0, dynamic_state=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:692
#27 launch_thread (d=0x7f87b34712c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:791
#28 0x00007f87b6caeaed in start_thread () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#29 0x00007f87b6d29768 in __clone3 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
Thread 2 (Thread 0x7f87b29526c0 (LWP 654) "guile"):
#0 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#1 0x00007f87b6cab788 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#2 0x00007f87b6cabd9c in __futex_abstimed_wait_common () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#3 0x00007f87b6cae1b8 in pthread_cond_wait@@GLIBC_2.3.2 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#4 0x00007f87b728e0f5 in scm_pthread_cond_wait (cond=<optimized out>, mutex=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1610
#5 0x00007f87b7290f9b in block_self (queue=0x7f87b6a74c40, mutex=mutex@entry=0x7f87b6a76fc0, waittime=waittime@entry=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:313
#6 0x00007f87b729393f in lock_mutex (kind=SCM_MUTEX_RECURSIVE, m=0x7f87b6a76fc0, current_thread=0x7f87b69776c0, waittime=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1025
#7 scm_timed_lock_mutex (mutex=0x7f87b6a74c30, timeout=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1090
#8 0x00007f87b67b07cf in ?? ()
#9 0x00007f87b69776c0 in ?? ()
#10 0x00007f87b485ad78 in ?? ()
#11 0x00007f87b69776c0 in ?? ()
#12 0x00007f87b724264b in scm_jit_enter_mcode (thread=0x7f87b69776c0, mcode=0x7f87b67a2100 "I211円314円I)304円I203円374円020円017円214円`002円") at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/jit.c:6061
#13 0x00007f87b72991b0 in vm_regular_engine (thread=0x7f87b485ad58) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:360
#14 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a24380, argv=<optimized out>, nargs=3) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#15 0x00007f87b721138f in scm_call_3 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>, arg3=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:510
#16 0x00007f87b723b600 in resolve_module (name=name@entry=0x7f87b48af420, public_p=public_p@entry=1 '001円') at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/intrinsics.c:320
#17 0x00007f87b723bec5 in resolve_module (name=0x7f87b48af420, public_p=1 '001円') at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/intrinsics.c:380
#18 lookup_bound_public (module=0x7f87b48af420, name=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/intrinsics.c:378
#19 0x00007f87b7299118 in vm_regular_engine (thread=0x7f87b69776c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:3474
#20 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b34a9f40, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#21 0x00007f87b720d678 in scm_call_with_unblocked_asyncs (proc=0x7f87b34a9f40) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/async.c:406
#22 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b69776c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#23 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b346d3c0, argv=<optimized out>, nargs=0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#24 0x00007f87b7293093 in really_launch (d=0x7f87b3494780) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:782
#25 0x00007f87b720fc3a in c_body (d=0x7f87b2951e00) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:430
#26 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b69776c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#27 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a17600, argv=<optimized out>, nargs=2) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#28 0x00007f87b721132a in scm_call_2 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:503
#29 0x00007f87b72bacd4 in scm_c_with_exception_handler.constprop.0 (type=0x404, handler_data=handler_data@entry=0x7f87b2951d90, thunk_data=thunk_data@entry=0x7f87b2951d90, thunk=<optimized out>, handler=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/exceptions.c:170
#30 0x00007f87b7293daf in scm_c_catch (tag=<optimized out>, body=<optimized out>, body_data=<optimized out>, handler=<optimized out>, handler_data=<optimized out>, pre_unwind_handler=<optimized out>, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/throw.c:168
#31 0x00007f87b72120b6 in scm_i_with_continuation_barrier (pre_unwind_handler=0x7f87b7211df0 <pre_unwind_handler>, body=0x7f87b720fc30 <c_body>, body_data=0x7f87b2951e00, handler=0x7f87b72187e0 <c_handler>, handler_data=0x7f87b2951e00, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:368
#32 scm_c_with_continuation_barrier (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:464
#33 0x00007f87b729300a in with_guile (base=0x7f87b2951e88, data=0x7f87b2951eb0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:649
#34 0x00007f87b7174198 in GC_call_with_stack_base () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#35 0x00007f87b728d22d in scm_i_with_guile (func=0x7f87b7293020 <really_launch>, data=0x7f87b3494780, dynamic_state=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:692
#36 launch_thread (d=0x7f87b3494780) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:791
#37 0x00007f87b6caeaed in start_thread () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#38 0x00007f87b6d29768 in __clone3 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
Thread 1 (Thread 0x7f87b6c19740 (LWP 648) "guile"):
#0 0x00007f87b6cb64fe in __syscall_cancel_arch () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#1 0x00007f87b6cab788 in __internal_syscall_cancel () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#2 0x00007f87b6cabd9c in __futex_abstimed_wait_common () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#3 0x00007f87b6cae1b8 in pthread_cond_wait@@GLIBC_2.3.2 () from /gnu/store/yj053cys0724p7vs9kir808x7fivz17m-glibc-2.41/lib/libc.so.6
#4 0x00007f87b728e0f5 in scm_pthread_cond_wait (cond=<optimized out>, mutex=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1610
#5 0x00007f87b7290f9b in block_self (queue=0x7f87b34a6340, mutex=mutex@entry=0x7f87b34aefc0, waittime=waittime@entry=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:313
#6 0x00007f87b7293685 in timed_wait (kind=SCM_MUTEX_STANDARD, m=0x7f87b34aefc0, c=0x7f87b34abed0, current_thread=0x7f87b6977d80, waittime=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1336
#7 scm_timed_wait_condition_variable (cond=0x7f87b34a6350, mutex=0x7f87b34a6320, timeout=0x904) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:1429
#8 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977d80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#9 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b695c030, argv=<optimized out>, nargs=1) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#10 0x00007f87b72116f7 in scm_primitive_eval (exp=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:671
#11 0x00007f87b7245c79 in scm_primitive_load (filename=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/load.c:131
#12 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977d80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#13 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b695c030, argv=<optimized out>, nargs=1) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#14 0x00007f87b72116f7 in scm_primitive_eval (exp=<optimized out>, exp@entry=0x7f87b6a98e40) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:671
#15 0x00007f87b72173e3 in scm_eval (exp=0x7f87b6a98e40, module_or_state=0x7f87b6a8cc80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:705
#16 0x00007f87b7275d00 in scm_shell (argc=4, argv=0x7ffdbfe33508) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/script.c:357
#17 0x00007f87b72286bc in invoke_main_func (body_data=0x7ffdbfe333a0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/init.c:312
#18 0x00007f87b720fc3a in c_body (d=0x7ffdbfe332c0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:430
#19 0x00007f87b7299340 in vm_regular_engine (thread=0x7f87b6977d80) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm-engine.c:972
#20 0x00007f87b72a7045 in scm_call_n (proc=0x7f87b6a17600, argv=<optimized out>, nargs=2) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/vm.c:1615
#21 0x00007f87b721132a in scm_call_2 (proc=<optimized out>, arg1=<optimized out>, arg2=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/eval.c:503
#22 0x00007f87b72bacd4 in scm_c_with_exception_handler.constprop.0 (type=0x404, handler_data=handler_data@entry=0x7ffdbfe33250, thunk_data=thunk_data@entry=0x7ffdbfe33250, thunk=<optimized out>, handler=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/exceptions.c:170
#23 0x00007f87b7293daf in scm_c_catch (tag=<optimized out>, body=<optimized out>, body_data=<optimized out>, handler=<optimized out>, handler_data=<optimized out>, pre_unwind_handler=<optimized out>, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/throw.c:168
#24 0x00007f87b72120b6 in scm_i_with_continuation_barrier (pre_unwind_handler=0x7f87b7211df0 <pre_unwind_handler>, body=0x7f87b720fc30 <c_body>, body_data=0x7ffdbfe332c0, handler=0x7f87b72187e0 <c_handler>, handler_data=0x7ffdbfe332c0, pre_unwind_handler_data=0x7f87b69f7500) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:368
#25 scm_c_with_continuation_barrier (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/continuations.c:464
#26 0x00007f87b729300a in with_guile (base=0x7ffdbfe33348, data=0x7ffdbfe33370) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:649
#27 0x00007f87b7174198 in GC_call_with_stack_base () from /gnu/store/y3m3cx1kjmyhakq5rakc0384pfdysdx5-libgc-8.2.8/lib/libgc.so.1
#28 0x00007f87b728df68 in scm_i_with_guile (func=<optimized out>, data=<optimized out>, dynamic_state=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:692
#29 scm_with_guile (func=<optimized out>, data=<optimized out>) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/threads.c:698
#30 0x00007f87b7231555 in scm_boot_guile (argc=argc@entry=4, argv=argv@entry=0x7ffdbfe33508, main_func=main_func@entry=0x401240 <inner_main>, closure=closure@entry=0x0) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/init.c:295
#31 0x00000000004010f6 in main (argc=4, argv=0x7ffdbfe33508) at /tmp/guix-build-guile-3.0.9.drv-0/guile-3.0.9/libguile/guile.c:94
```
Looks like thread 1 (which is not running Fibers) is stuck in `wait-condition-variable` (from `suspend` in `perform-operation`).