I also just upgraded to 25.12 with a working RSyslog configuration in 24.10, rsyslog is now segfaulting as well. I use plain tcp transport. As asked in 244506 I enabled coredumps and tried to get a backtrace with gdb but i guess since I dont have an executable with debug symbols it wont help much.
root@c2600wifi:~# file /mnt/sda1/coredump/w1!imtcp-1774650931.core
/mnt/sda1/coredump/w1!imtcp-1774650931.core: ELF 32-bit LSB core file, ARM, version 1 (SYSV), SVR4-style, from 'rsyslogd -dn', real uid: 0, effective uid: 0, real gid: 0, effective gid: 0, e
xecfn: '/usr/sbin/rsyslogd', platform: 'v7l'
root@c2600wifi:~# gdb /usr/sbin/rsyslogd /mnt/sda1/coredump/w1!imtcp-1774650931.core
GNU gdb (GDB) 16.3
Copyright (C) 2024 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
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This GDB was configured as "arm-openwrt-linux".
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Reading symbols from /usr/sbin/rsyslogd...
(No debugging symbols found in /usr/sbin/rsyslogd)
[New LWP 10248]
[New LWP 10247]
[New LWP 10246]
[New LWP 10245]
[New LWP 10249]
[New LWP 10250]
[New LWP 10244]
Core was generated by `/usr/sbin/rsyslogd -dn'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0xb6e39974 in ?? ()
[Current thread is 1 (LWP 10248)]
root@c2600wifi:~# gdb
GNU gdb (GDB) 16.3
Copyright (C) 2024 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "arm-openwrt-linux".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
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Type "apropos word" to search for commands related to "word".
(gdb) file /usr/sbin/rsyslogd
Reading symbols from /usr/sbin/rsyslogd...
(No debugging symbols found in /usr/sbin/rsyslogd)
(gdb) run -f /var/etc/rsyslog.conf -n
Starting program: /usr/sbin/rsyslogd -f /var/etc/rsyslog.conf -n
rsyslogd: module 'imuxsock' already in this config, cannot be added [v8.2506.0 try https://www.rsyslog.com/e/2221 ]
rsyslogd: module 'imklog' already in this config, cannot be added [v8.2506.0 try https://www.rsyslog.com/e/2221 ]
[New LWP 10455]
[New LWP 10456]
[New LWP 10457]
[New LWP 10458]
[New LWP 10459]
Thread 1 "rsyslogd" received signal SIGTTOU, Stopped (tty output).
0xb6fca3ec in ?? ()
(gdb) bt
#0 0xb6fca3ec in ?? ()
#1 0x0002b188 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
Switching the transport to udp would work around the bugged plain tcp transport. Is there anything else we can do here? Is there a noob friendly way to get the debug symbols?