Command Section
KGDB(1)                 FreeBSD General Commands Manual                KGDB(1)

     kgdb - kernel debugger

     kgdb [-a | -f | -fullname] [-b rate] [-q | -quiet] [-v] [-w]
          [-d crashdir] [-c core | -n dumpnr | -r device] [kernel [core]]

     This version of kgdb is deprecated and will be removed from future
     versions of the FreeBSD base system.  A newer version of kgdb is
     available from ports or packages (devel/gdb).

     The kgdb utility is a debugger based on gdb(1) that allows debugging of
     kernel core files.

     The options are as follows:

     -a                 Increase the annotation level.  An annotation level of
                        1 features the historical -fullname option of gdb(1).
                        This is useful when running kgdb in Emacs.  The -f or
                        -fullname options are supported for backward
                        compatibility as well.

     -b rate            Set the baudrate to rate.

     -q                 Suppress printing of the banner when the debugger
                        starts.  The -quiet form is supported for
                        compatibility as well.

     -v                 Increase verbosity.

     -w                 Opens kmem-based targets in read-write mode.  (This is
                        identical to what --wcore used to do in previous gdb
                        versions for FreeBSD.)

     -d crashdir        Use crashdir instead of the default, /var/crash to
                        locate kernel core dump files in.  The name vmcore.
                        plus the dump number will be appended to determine the
                        actual dump file name.

     -c core            Explicitly use core as the core dump file.

     -n dumpnr          Use the kernel core dump file numbered dumpnr for

     -r device          Use device to connect kgdb to for a remote debugging

     The -c, -n, and -r options are mutually exclusive.

     Optionally, the name of the kernel symbol file and the name of the core
     dump file can be supplied on the command-line as positional arguments.
     If no kernel symbol file name has been given, the symbol file of the
     currently running kernel will be used.  If no core dump file has been
     specified through either of the options or the last command-line
     argument, /dev/mem will be opened to allow debugging the currently
     running kernel.

     /dev/mem        Default memory image to open if no core dump file has
                     been specified.

     /var/crash      Default directory to locate kernel core dump files.


     The kgdb utility first appeared in its current form in FreeBSD 5.3.

FreeBSD 11.1-RELEASE-p4          July 5, 2017          FreeBSD 11.1-RELEASE-p4
Command Section