Bug#743184: perl: SpamAssassin spamd segfaults since updating servers to Debian wheezy

[Martin von Wittich]

Package: perl
Version: 5.14.2-21+deb7u1
Severity: normal

Dear Maintainer,

since we've updated our customer servers (about 1000) to Debian wheezy,
we're seeing a lot of "spamd child" segfaults on many of these servers.
I've already filed a bug to the spamassassin package[1] back in Dec 2013
when we first noticed the issue, but after investigating the issue, I
think I've now isolated the cause in the Debian packaging of Perl
itself, so I'm filing this bug now against the Perl package.

The symptom of the issue is that dmesg/syslog report a lot of segfaults
of spamd (which is a Perl script):

host ~ # zgrep segfault /var/log/syslog*
/var/log/syslog:Dec 18 11:03:23 iserv kernel: [21705301.867857] spamd child[6661]: segfault at 127 ip 0811a0ca sp bfd468a0 error 4 in perl[8048000+169000]
/var/log/syslog.1:Dec 17 18:36:18 iserv kernel: [21646077.256066] spamd child[17653]: segfault at 1dc ip 080f1543 sp bf9963b0 error 4 in perl[8048000+169000]
/var/log/syslog.1:Dec 17 18:36:20 iserv kernel: [21646079.152118] spamd child[17657]: segfault at 41485851 ip 0810c14d sp bf996fb0 error 4 in perl[8048000+169000]
/var/log/syslog.1:Dec 17 18:36:30 iserv kernel: [21646088.667283] spamd child[4999]: segfault at 1f3 ip 0811a0ca sp bf9963c0 error 4 in perl[8048000+169000]
/var/log/syslog.1:Dec 17 18:36:33 iserv kernel: [21646091.712060] spamd child[17728]: segfault at 1dc ip 0811a0ca sp bf9963c0 error 4 in perl[8048000+169000]
[...]

In the last seven days, spamd segfaulted on 64 of our customer servers (out of
a total of 932 servers that I checked). I have attached three backtraces to the
original spamd bug report; please see those for details.

To isolate the issue, I have run the following experiments on one of the
affected servers (SA = SpamAssassin):

2014-02-13   I installed SA 3.4.0 manually with cpanm[2].

2014-02-25   spamd has crashed 10 times since 2014-02-14,
             so a manual SA installation didn't resolve it.
2014-02-25   I compiled Perl 5.18.2 with Perlbrew[3] and again
             installed SA 3.4.0 with cpanm.

2014-03-10   spamd has crashed 0 times since 2014-02-26, so the custom
             Perl 5.18.2 build doesn't seem to be affected.
2014-03-10   I compiled Perl 5.14.2 with Perlbrew and SA 3.4.0
             with cpanm to make sure that the issue isn't caused by
             a Perl bug that may have been fixed in Perl 5.18.2.

2014-03-28   spamd has crashed 0 times since 2014-03-11,
             so the custom Perl 5.14.2 build isn't affected either.

This leads me to my conclusion that the issue must be somehow caused by the
Debian packaging of Perl... maybe a Debian patch or something?

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=732550
[2] http://search.cpan.org/~miyagawa/App-cpanminus-1.7001/bin/cpanm
[3] http://perlbrew.pl/

-- System Information:
Debian Release: 7.4
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: i386 (x86_64)
Foreign Architectures: amd64

Kernel: Linux 3.10-0.bpo.3-amd64 (SMP w/8 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages perl depends on:
ii  libbz2-1.0    1.0.6-4
ii  libc6         2.13-38+deb7u1
ii  libdb5.1      5.1.29-5
ii  libgdbm3      1.8.3-11
ii  perl-base     5.14.2-21+deb7u1
ii  perl-modules  5.14.2-21+deb7u1
ii  zlib1g        1:1.2.7.dfsg-13

Versions of packages perl recommends:
ii  netbase  5.0

Versions of packages perl suggests:
pn  libterm-readline-gnu-perl | libterm-readline-perl-perl  <none>
ii  make                                                    3.81-8.2
ii  perl-doc                                                5.14.2-21+deb7u1

-- no debconf information