GNU bug report logs - #42353
mcron occasionally gets stuck in pre-fork

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 42353 in the body.
You can then email your comments to 42353 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Ludovic Courtès <ludo <at> gnu.org>
To: <bug-guix <at> gnu.org>
Subject: mcron occasionally gets stuck in pre-fork
Date: Tue, 14 Jul 2020 16:16:50 +0200

Hi,

mcron running on top of Guile 3.0.2 occasionally gets stuck right before
fork while shutting down the finalization thread:

--8<---------------cut here---------------start------------->8---
ludo <at> berlin ~$ ps aux|grep 25457
root      25457  0.0  0.0 149576  9412 ?        Ssl  Jul10   0:00 /gnu/store/fp5ybkawldy28kzkzp60s23hkqbdx4x2-mcron-1.1.4/bin/mcron /gnu/store/l74fbl7si93si6x47sfwsnc9ag386570-mcron-job /gnu/store/r11ffr5rfkqyw1drqrqabwx210lk1jfn-mcron-job /gnu/store/3a88kc90lv6nqy9k1bwkxpi9gps1vfdb-mcron-job /gnu/store/8386w15b7mj1pmjbp5n9jk6p2v9b0m2q-mcron-job /gnu/store/v0jwrr7ggwvr6y4xvqwiqksbrgkmm21c-mcron-job /gnu/store/wzv96j9c1h86kfzl5ai64j1xwvkin1wz-mcron-job /gnu/store/kz93w89b7sj6gz32aq6flsy0pa3ag6ny-mcron-job /gnu/store/4jv4ap1d161dvix472j47lipvqafqrmn-mcron-job /gnu/store/r7vs7vkid8w1xz0nzkcwc6ylmz8yryc5-mcron-job /gnu/store/yy51bjcx0zndsn9db56sb2d1bn7c9j1i-mcron-job /gnu/store/56vfqmzfidcf1axh07zak2gfbgrc8jdm-mcron-job
ludo     130462  0.0  0.0   6376  2476 pts/11   S+   16:10   0:00 grep --color 25457
ludo <at> berlin ~$ sudo gdb -ix ~/.gdbinit -p 25457
GNU gdb (GDB) 8.3.1

[…]

(gdb) bt
#0  0x00007f38221a1517 in __pthread_clockjoin_ex ()
   from /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/lib/libpthread.so.0
#1  0x00007f38222960d8 in stop_finalization_thread () at finalizers.c:276
#2  0x00007f38222962f9 in scm_i_finalizer_pre_fork () at finalizers.c:301
#3  0x00007f382231e1d6 in scm_fork () at posix.c:1230
#4  0x00007f38193b2def in ?? ()
#5  0x00007f3821bc9d80 in ?? ()
#6  0x00007f38223795c0 in ?? ()
   from /gnu/store/18hp7flyb3yid3yp49i6qcdq0sbi5l1n-guile-3.0.2/lib/libguile-3.0.so.1
#7  0x00007f3821bc9d80 in ?? ()
#8  0x00007f38222b2f0b in scm_jit_enter_mcode (thread=0x7f3821bc9d80,
    mcode=0x7f38193accd2 "I\211\314I)\304I\203\374\060\017\214s\003")
    at jit.c:5777
#9  0x00007f382230e350 in vm_regular_engine (thread=0x7f38193b2dd0)
    at vm-engine.c:546
#10 0x00007f382230f175 in scm_call_n (proc=<optimized out>,
    argv=argv <at> entry=0x7ffd8ff6ad58, nargs=nargs <at> entry=1) at vm.c:1608
#11 0x00007f382228c078 in scm_call_1 (proc=<optimized out>,
    arg1=<optimized out>) at eval.c:496
#12 0x000000000040130c in inner_main ()
#13 0x00007f38222a4c0d in invoke_main_func (body_data=0x7ffd8ff6b240)
    at init.c:308

[…]

(gdb) thread apply all bt
Thread 17 (Thread 0x7f3819c7d700 (LWP 15795)):
#0  0x00007f38221aa0a4 in read () from /gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/lib/libpthread.so.0
#1  0x00007f3822296067 in read_finalization_pipe_data (data=0x7f3819c7ca30) at finalizers.c:205
#2  0x00007f38221e8d94 in GC_do_blocking_inner () from /gnu/store/zg126cjicrpm2p6zc08ra5vh4ddag7ww-libgc-8.0.4/lib/libgc.so.1
#3  0x00007f38221e59c2 in GC_with_callee_saves_pushed () from /gnu/store/zg126cjicrpm2p6zc08ra5vh4ddag7ww-libgc-8.0.4/lib/libgc.so.1
#4  0x00007f38221e5a6c in GC_do_blocking () from /gnu/store/zg126cjicrpm2p6zc08ra5vh4ddag7ww-libgc-8.0.4/lib/libgc.so.1
#5  0x00007f38223036b5 in scm_without_guile (func=0x7f3822296050 <read_finalization_pipe_data>, data=0x7f3819c7ca30) at threads.c:706
#6  0x00007f382229641b in finalization_thread_proc (unused=<optimized out>) at finalizers.c:218
--8<---------------cut here---------------end--------------->8---

This reminds me of <https://issues.guix.info/31925> and more recently
this issue Mathieu reported: <https://issues.guix.gnu.org/41948>.

It could be that Guile still has troubles shutting down the finalization
thread.

Ludo’.

Message #12 received at 42353-done <at> debbugs.gnu.org (full text, mbox):

From: Maxim Cournoyer <maxim.cournoyer <at> gmail.com>
To: Ludovic Courtès <ludo <at> gnu.org>
Cc: Mathieu Othacehe <othacehe <at> gnu.org>, 42353-done <at> debbugs.gnu.org
Subject: Re: bug#42353: mcron occasionally gets stuck in pre-fork
Date: Mon, 23 Aug 2021 23:41:02 -0400

Hello,

Ludovic Courtès <ludo <at> gnu.org> writes:

> Hi,
>
> mcron running on top of Guile 3.0.2 occasionally gets stuck right before
> fork while shutting down the finalization thread:
>

[...]

> This reminds me of <https://issues.guix.info/31925> and more recently

This issue was closed as non-reproducible.

> this issue Mathieu reported: <https://issues.guix.gnu.org/41948>.

This one is supposedly fixed in Guile 3.0.7 (yay!).

As core-updates-frozen is currently on using Guile 3.0.7, I'm
tentatively closing this issue.

Thanks,

Maxim

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.