Subject: bug#908: rsyslog: segfaults when run against libfastjson4 > 0.99.9-1

From: Arthur Marsh <[email-masked]>
Date: Sat, 06 Sep 2025 10:34:33 +0930

Package: rsyslog
Version: 8.2504.0-1devuan1
Severity: normal

Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?

With libfastjson4 1.2304.0-1 and later I get:

Starting enhanced syslogd: rsyslogd/usr/sbin/rsyslogd: Relink `/lib/x86_64-linux-gnu/libfastjson.so.4' with `/lib/x86_64-linux-gnu/libm.so.6' for IFUNC symbol `modf'
Segmentation fault
 failed!

   * What exactly did you do (or not do) that was effective (or
     ineffective)?

Downgrading libfastjson4 to 0.99.9-1 enabled rsyslog to start normally.
   * What was the outcome of this action?
   * What outcome did you expect instead?

*** End of the template - remove these template lines ***

-- System Information:
Distributor ID:	Devuan
Description:	Devuan GNU/Linux 6 (excalibur/ceres)
Release:	6
Codename:	excalibur ceres
Architecture: x86_64

Kernel: Linux 6.17.0-rc4+ (SMP w/12 CPU threads; PREEMPT)
Kernel taint flags: TAINT_USER
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB
Shell: /bin/sh linked to /usr/bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages rsyslog depends on:
ii  init-system-helpers        1.68devuan1
ii  libc6                      2.42-1
ii  libestr0                   0.1.11-2
ii  libfastjson4               0.99.9-1
ii  liblognorm5                2.0.6-5
ii  libuuid1                   2.41-5devuan2
ii  libzstd1                   1.5.7+dfsg-1.1
ii  lsb-base                   11.6
ii  sysvinit-utils [lsb-base]  3.14-4devuan1
ii  zlib1g                     1:1.3.dfsg+really1.3.1-1+b1

Versions of packages rsyslog recommends:
ii  logrotate  3.22.0-1

Versions of packages rsyslog suggests:
pn  rsyslog-clickhouse                <none>
pn  rsyslog-doc                       <none>
pn  rsyslog-docker                    <none>
pn  rsyslog-elasticsearch             <none>
pn  rsyslog-gssapi                    <none>
pn  rsyslog-hiredis                   <none>
pn  rsyslog-kafka                     <none>
pn  rsyslog-kubernetes                <none>
pn  rsyslog-mongodb                   <none>
pn  rsyslog-mysql | rsyslog-pgsql     <none>
pn  rsyslog-openssl | rsyslog-gnutls  <none>
pn  rsyslog-relp                      <none>
pn  rsyslog-snmp                      <none>

-- no debconf information