Re: SIGFPE in s6-rc-init 3.0.0 etc,...

From: Steffe - <stefffe_at_gmail.com>
Date: Fri, 22 Dec 2017 23:33:25 +0100

Den 2017-12-17 kl. 20:26, skrev Stefan Nilsson:

Den 2017-12-15 kl. 13:08, skrev Laurent Bercot:

When buildroot 2017.11 was released, I was thrilled to see new versions of
s6 in it (s6-rc 0.3.0.0, skalibs 2.6.0.1 and s6 2.6.1.1), but when booting
up I immediately got a SIGFPE in s6-rc-init,... I ran it through strace and
the result can be seen here: http://steffe.net/s6-sigfpe.txt

It crashes at the exact same place if I re-run it, and it crashes every
time.


  Thanks for the report - it's very interesting. As Rasmus said, a
similar error during s6-rc-init happened before, but was never
reproducible. I've gone over the incriminated code several times, but
was unable to find a bug. :/
  The SIGFPE sounds very weird because s6-rc doesn't use floating point
anywhere, but if it's hitting undefined behaviour then everything is
possible.
  Can you somehow valgrind or gdb your s6-rc-init binary? I understand
it's on an embedded system, which can make it hard, but on my development
machines I just cannot reproduce the problem


I was able to build the image for my target system and run it in qemu and
still reproduce the problem. I first ran it through valgrind which
pinpoints a few possible issues:
http://steffe.net/s6/valgrind_nodebug.txt

Then I ran it through gdb and just did a "bt", let me know if I can help
you with more information here, I am not a gdb expert:
http://steffe.net/s6/gdb_nodebug.txt

Since the binaries are stripped, information is kind of rough. However,
when rebuilding with debug enabled I can not reproduce the issue any
more,... :o/

Best Regards
Stefan Nilsson

It seems my mails are not accepted by the list after switching to a new
SMTP relay (Mailjet),... So re-sending via gmail instead,...

// Stefan
Received on Fri Dec 22 2017 - 22:33:25 UTC

This archive was generated by hypermail 2.3.0 : Sun May 09 2021 - 19:38:49 UTC