monit 5.12 segfault on EL 7

[Nathan Williams]

trying to build monit 5.12 from source on EL7, the build completes, but hitting a segfault trying to launch the daemon. does not happen with 5.11, so seems to be something in the latest release.

not hitting a segfault doing something simple like checking the version, so something with the config maybe?

attaching strace of segfault and config dump. let me know if i can help collect any other info!

[Nathan Williams]

core collected from:

[root@monit-ng-source-centos-70 ~]# /usr/local/bin/monit -vI Adding host allow 'localhost' Skipping redundant host 'localhost' Skipping redundant host 'localhost' Skipping redundant host 'localhost' Skipping redundant host 'localhost' Skipping redundant host 'localhost' Cannot translate 'monit-ng-source-centos-70.vagrantup.com' to FQDN name -- Name or service not known Segmentation fault (core dumped)

[Tildeslash]

Thanks for data, i'm sorry i'm unable to replicate the problem (using CentOS 7.0.1406) - using the same configuration.

Please can you yet provide the backtrace from the coredump?:

gdb /usr/local/bin/monit core.29755
gdb> thr apply all bt

Please can you also test with the pre-compiled binary?: http://mmonit.com/monit/dist/binary/5.12/monit-5.12-linux-x64.tar.gz

[Michael Bakker]

Guten Tag,

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Mit freundlichen Grüßen Michael Bakker

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[Nathan Williams]

regenerated a new coredump since the old one got destroyed along with the test instance, attaching here for reference:

[root@monit-ng-source-centos-70 ~]# ulimit -c unlimited
[root@monit-ng-source-centos-70 ~]# /usr/local/bin/monit -vI
Adding host allow 'localhost'
Skipping redundant host 'localhost'
Skipping redundant host 'localhost'
Skipping redundant host 'localhost'
Skipping redundant host 'localhost'
Skipping redundant host 'localhost'
Cannot translate 'monit-ng-source-centos-70.vagrantup.com' to FQDN name -- Name or service not known
Segmentation fault (core dumped)
[root@monit-ng-source-centos-70 ~]# ls
anaconda-ks.cfg  core.29748
[root@monit-ng-source-centos-70 ~]# gdb /usr/local/bin/monit core.29748 
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-51.el7
Copyright (C) 2013 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 "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/local/bin/monit...done.
[New LWP 29748]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Core was generated by `/usr/local/bin/monit -vI'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007f701beca213 in freeaddrinfo () from /lib64/libc.so.6
Missing separate debuginfos, use: debuginfo-install audit-libs-2.3.3-4.el7.x86_64 glibc-2.17-55.el7_0.5.x86_64 keyutils-libs-1.5.8-3.el7.x86_64 krb5-libs-1.11.3-49.el7.x86_64 libcom_err-1.42.9-4.el7.x86_64 libselinux-2.2.2-6.el7.x86_64 nss-softokn-freebl-3.15.4-2.el7.x86_64 openssl-libs-1.0.1e-34.el7_0.7.x86_64 pam-1.1.8-9.el7.x86_64 pcre-8.32-12.el7.x86_64 xz-libs-5.1.2-8alpha.el7.x86_64 zlib-1.2.7-13.el7.x86_64
(gdb) thr apply all bt

Thread 1 (Thread 0x7f701d49f840 (LWP 29748)):
#0  0x00007f701beca213 in freeaddrinfo () from /lib64/libc.so.6
#1  0x0000000000427acf in Util_getfqdnhostname (buf=buf@entry=0x7fff2490f400 "monit-ng-source-centos-70.vagrantup.com", 
    len=len@entry=256) at src/util.c:1941
#2  0x00000000004135af in postparse () at src/p.y:2366
#3  parse (controlfile=0x10dd2a0 "/etc/monitrc") at src/p.y:2253
#4  0x0000000000415a65 in do_init () at src/monit.c:270
#5  0x000000000040be85 in main (argc=2, argv=0x7fff2490f678) at src/monit.c:169

[Nathan Williams]

ugh. so on a hunch, i just fully upgraded the test instance before compiling, and the issue's no longer occurring; sorry for the hassle, feel free to close this out.

[Tildeslash]

fix Issue #155 : Monit may crash if the system hostname resolving failed.

→ <<cset 64fdf3195f3e>>

[Tildeslash]

Thanks for data, the bug was real and is fixed now.

[Nathan Williams]

oh, that's great! thanks for the guidance on debugging and the fast resolution!

[Tildeslash]

Removing version: 5.12 (automated comment)