DragonFly On-Line Manual Pages
KGDB(1) DragonFly General Commands Manual KGDB(1)
kgdb -- kernel debugger
kgdb [-a | -f | -fullname] [-q | -quiet] [-t | -tui-mode] [-v] [-w]
[-d crashdir] [-c core | -n dumpnr | -r device] [kernel [core]]
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.
-q Suppress printing of the banner when the debugger starts.
The -quiet form is supported for compatibility as well.
-t Activate the Text User Interface (TUI). The -tui-mode shows
the source file, assembly output, program registers and gdb
commands in separate text windows. It implicitly sets the
-quiet option as well.
-v Increase verbosity.
-w Opens kmem-based targets in read-write mode.
-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
-c core Explicitly use core as the core dump file.
-n dumpnr Use the kernel core dump file numbered dumpnr for debugging.
-r device Use device to connect kgdb to for a remote debugging ses-
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 cur-
rently running kernel will be used. If no core dump file has been speci-
fied 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
/var/crash Default directory to locate kernel core dump files.
The kgdb utility first appeared in its current form in FreeBSD 5.3 and
was later ported to DragonFly 1.5.
DragonFly 4.1 May 15, 2012 DragonFly 4.1