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Debugging with gdb on FreeNAS

Debugging with gdb on FreeNAS

Jul 27, 2016

In case the UrBackup server crashes on FreeNAS a gdb stacktrace is a very helpful tool in finding the cause of the crash.

 

Steps to get a gdb backtrace:

 

  1. Enter the shell of the UrBackup jail

  2. Install gdb in the shell via the command
    pkg_add -r gdb

  3. Shutdown the urbackup server:
    killall urbackupsrv

  4. Install tmux:
    pkg_add -r tmux

  5. Run tmux:
    tmux

  6. Start the UrBackup server in gdb:
    gdb --args /usr/local/sbin/urbackupsrv run -g 104857600 -u root

  7. Start the program in gdb:
    run

  8. Once it crashed enter the shell of the plugin jail again and attach to the tmux session:
    tmux attach

  9. Enter "bt" to get the backtrace to the location it crashed:
    bt

  10. Add the trace information to your bug report

 

How to get debug logging info:

  1. Export the Plugin filesystem via filesharing

  2. Access debug logfile at JAIL_ROOT/var/log