A kernel debugger is a

debugger A debugger or debugging tool is a computer program used to test and debug other programs (the "target" program). The main use of a debugger is to run the target program under controlled conditions that permit the programmer to track its executi ...

present in some

operating system kernels The kernel is a computer program at the core of a computer's operating system and generally has complete control over everything in the system. It is the portion of the operating system code that is always resident in memory and facilitates i ...

to ease debugging and kernel development by the kernel developers. A kernel debugger might be a stub implementing low-level operations, with a full-blown debugger such as

GNU Debugger The GNU Debugger (GDB) is a portable debugger that runs on many Unix-like systems and works for many programming languages, including Ada, C, C++, Objective-C, Free Pascal, Fortran, Go, and partially others. History GDB was first written ...

(gdb), running on another machine, sending commands to the stub over a

serial line Serial may refer to: Arts, entertainment, and media The presentation of works in sequential segments * Serial (literature), serialised literature in print * Serial (publishing), periodical publications and newspapers * Serial (radio and televisio ...

or a network connection, or it might provide a command line that can be used directly on the machine being debugged. Operating systems and operating system kernels that contain a kernel debugger: * The

Windows NT Windows NT is a proprietary graphical operating system produced by Microsoft, the first version of which was released on July 27, 1993. It is a processor-independent, multiprocessing and multi-user operating system. The first version of Win ...

family includes a kernel debugger named KD, which can act as a local debugger with limited capabilities (reading and writing kernel memory, and setting breakpoints) and can attach to a remote machine over a serial line,

IEEE 1394 IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony an ...

connection,

USB 2.0 Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...

USB 3.0 USB 3.0, released in November 2008, is the third major version of the Universal Serial Bus (USB) standard for interfacing computers and electronic devices. Among other improvements, USB 3.0 adds the new transfer rate referred to as '' ...

connection. The

WinDbg WinDbg is a multipurpose debugger for the Microsoft Windows computer operating system, distributed by Microsoft. Debugging is the process of finding and resolving errors in a system; in computing it also includes exploring the internal operation ...

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

debugger can also be used to debug kernels on local and remote machines. * BeOS and

Haiku is a type of short form poetry originally from Japan. Traditional Japanese haiku consist of three phrases that contain a ''kireji'', or "cutting word", 17 '' on'' (phonetic units similar to syllables) in a 5, 7, 5 pattern, and a ''kigo'', or s ...

include a kernel debugger usable with either an on-screen console or over a serial line. It features various commands to inspect memory, threads, and other kernel structures. *

DragonFly BSD DragonFly BSD is a free and open-source Unix-like operating system forked from FreeBSD 4.8. Matthew Dillon, an Amiga developer in the late 1980s and early 1990s and FreeBSD developer between 1994 and 2003, began working on DragonFly BSD in ...

* Linux kernel; No kernel debugger was included in the mainline Linux tree prior to version 2.6.26-rc1 because

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and, historically, the lead developer of the Linux kernel, used by Linux distributions and other operating systems such as Android. He also ...

didn't want a kernel debugger in the kernel. ** KDB (local) ** KGDB (remote) ** MDB (local/remote) * NetBSD (DDB for local, KGDB for remote) *

macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

, Darwin which runs the XNU kernel using the Mach component * OpenBSD includes ddb which has a syntax is similar to

References

Debuggers Operating system kernels {{Comp-sci-stub