Subject: bug#929: rsyslog: segfaults with latest libc6 (2.42-4)

From: "Dimitris T." <[email-masked]>
Date: Thu, 04 Dec 2025 14:15:45 +0200

Package: rsyslog
Version: 8.2510.0-5devuan1
Severity: grave
Justification: renders package unusable

Hey,
since upgrading libc6 today, rsyslog fails with following message : 

# /usr/sbin/rsyslogd -n -iNONE
/usr/sbin/rsyslogd: Relink `/usr/lib/x86_64-linux-gnu/libfastjson.so.4' with `/usr/lib/x86_64-linux-gnu/libm.so.6' for IFUNC symbol `modf'
Segmentation fault

dmesg : 
rsyslogd[4291]: segfault at 9c ip 00007fb603e233a7 sp 00007ffe50362148 error 4 in libm.so.6[4b3a7,7fb603de9000+82000] likely on CPU 2 (core 0, socket 0)

after downgrading libc6, libc6-bin, locales to testing version (2.41-12) , rsyslog works again as it should.

thanks,
d.

-- System Information:
Distributor ID:	Devuan
Description:	Devuan GNU/Linux 7 (freia/ceres)
Release:	7
Codename:	freia ceres
Architecture: x86_64

Kernel: Linux 6.17.9+deb14-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=el_GR.UTF-8, LC_CTYPE=el_GR.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: runit (via /run/runit.stopit)
LSM: AppArmor: enabled

Versions of packages rsyslog depends on:
ii  init-system-helpers        1.69devuan1
ii  libc6                      2.42-4
ii  libestr0                   0.1.11-2
ii  libfastjson4               1.2304.0-2
ii  liblognorm5                2.0.7-1
ii  libuuid1                   2.41.2-4devuan1
ii  libzstd1                   1.5.7+dfsg-2
ii  lsb-base                   11.6
ii  sysvinit-utils [lsb-base]  3.15-6devuan1
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                     <none>
pn  rsyslog-openssl | rsyslog-gnutls  <none>
pn  rsyslog-pgsql                     <none>
pn  rsyslog-relp                      <none>
pn  rsyslog-snmp                      <none>

-- Configuration Files:
/etc/logrotate.d/rsyslog [file not found]

-- no debconf information