Please follow the steps below before submitting a bug.

It is important to determine what is hanging, i.e. whether it is CFEngine itself or something that CFEngine is interacting with. Run the program with -v and -d flags to see if it has gone into an infinite loop, or if it is waiting for something.

Common causes of hanging processes:

• Berkeley DB database corruption: try to delete *_db files in /var/cfengine
• Command processes that do not properly close their file descriptiors of child processes. Try running the commands with a shell enabled (use_shell => "yes") and use </dev/null >/dev/null to close the descriptors.

Segfaults in CFEngine may be caused by the incorrect build environment or by bugs in CFEngine or the libraries it uses.

• Install gdb.
• Download gdbscript and save it to /var/cfengine/bin/gdbscript.
• Prepend /var/cfengine/bin/gdbscript to the command line to run the faulting component, ** for all components, add --verbose option. ** for daemons, add --no-fork option. For example:

# /var/cfengine/bin/gdbscript /var/cfengine/bin/cf-serverd --no-fork &
[1] 18790
# outputting trace to '/root/cfgdb-cf-serverd.txt'
[1]+  Done                    /var/cfengine/bin/gdbscript cf-serverd --no-fork
# grep SIGSEGV /root/cfgdb-cf-serverd.txt
Program received signal SIGSEGV, Segmentation fault.

Obtain the trace from /root/cfgdb-*.txt

• Install Valgrind.
• Run the leaking CFEngine component inside valgrind ** for all components, add --verbose option. ** for daemons, ad --no-fork option.

For example:

valgrind --leak-check=full \
  /var/cfengine/bin/cf-serverd --no-fork 2>/root/valgrind-cf-serverd &

• If you are debugging a daemon, let it run for such a long time that you are confident that the consumed memory is a bug (remember that valgrind also consumes memory).
• Send SIGINT to the valgrind process (prefixed memcheck)

# ps -e|grep mem
 2194 pts/0    00:00:24 memcheck-x86-li
# kill -SIGINT 2194

After a successful memory trace has been obtained in /root/valgrind-*.txt, check the end of the trace to verify that at least 10-20MB are lost. Otherwise, rerun the tracing for a longer period of time to gather enough data.

Probably CFEngine is getting stuck on the long task. Kill the existing processes, and run cf-agent -v to see what's going on.

This is not a bug, but a feature. Have a look at [["Locks" section|https://cfengine.com/manuals/cf3-reference#When-and-where-are-promises-made_003f]] in Reference Manual.