A kernel debugger is a

debugger A debugger is a computer program used to test and debug other programs (the "target" programs). Common features of debuggers include the ability to run or halt the target program using breakpoints, step through code line by line, and display ...

present in some

operating system kernels A kernel is a computer program at the core of a computer's operating system that always has complete control over everything in the system. The kernel is also responsible for preventing and mitigating conflicts between different processes. It is ...

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, Assembly, C, C++, D, Fortran, Haskell, Go, Objective-C, OpenCL C, Modula-2, Pascal, Rust, and par ...

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

serial line A serial port is a serial communication interface through which information transfers in or out sequentially one bit at a time. This is in contrast to a parallel port, which communicates multiple bits simultaneously in parallel. Throughout m ...

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 software, proprietary Graphical user interface, graphical operating system produced by Microsoft as part of its Windows product line, the first version of which, Windows NT 3.1, was released on July 27, 1993. Original ...

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 a ...

connection,

USB 2.0 Universal Serial Bus (USB) is an industry standard, developed by USB Implementers Forum (USB-IF), for digital data transmission and power delivery between many types of electronics. It specifies the architecture, in particular the physical i ...

USB 3.0 Universal Serial Bus 3.0 (USB 3.0), marketed as SuperSpeed USB, is the third major version of the Universal Serial Bus (USB) standard for interfacing computers and electronic devices. It was released in November 2008. The USB 3.0 specification ...

connection. The

WinDbg WinDbg is a multipurpose debugger for the Microsoft Windows computer operating system, distributed by Microsoft. It can be used to debug user mode applications, device drivers, and the operating system itself in kernel mode. Overview Like the ...

GUI Gui or GUI may refer to: People Surname * Gui (surname), an ancient Chinese surname, ''xing'' * Bernard Gui (1261 or 1262–1331), inquisitor of the Dominican Order * Luigi Gui (1914–2010), Italian politician * Gui Minhai (born 1964), Ch ...

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

BeOS BeOS is a discontinued operating system for personal computers that was developed by Be Inc. It was conceived for the company's BeBox personal computer which was released in 1995. BeOS was designed for multitasking, multithreading, and a graph ...

and

Haiku is a type of short form poetry that originated in Japan. Traditional Japanese haiku consist of three phrases composed of 17 Mora (linguistics), morae (called ''On (Japanese prosody), on'' in Japanese) in a 5, 7, 5 pattern; that include a ''kire ...

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. In Haiku, the debugger is called "Kernel Debugging Land" (KDL). *

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 The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...

; 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 lead developer of the Linux kernel. He also created the distributed version control system Git. He was honored, along with Shinya Yam ...

didn't want a kernel debugger in the kernel. ** KDB (local) **

KGDB KGDB is a debugger for the Linux kernel and the kernels of NetBSD and FreeBSD. It requires two machines that are connected via a serial connection. The serial connection may either be an RS-232 interface using a null modem cable, or via the U ...

(remote) ** MDB (local/remote) *

NetBSD NetBSD is a free and open-source Unix-like operating system based on the Berkeley Software Distribution (BSD). It was the first open-source BSD descendant officially released after 386BSD was fork (software development), forked. It continues to ...

has DDB for local and KGDB for remote. *

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

has ddb for local and kdp for remote. *

OpenBSD OpenBSD is a security-focused operating system, security-focused, free software, Unix-like operating system based on the Berkeley Software Distribution (BSD). Theo de Raadt created OpenBSD in 1995 by fork (software development), forking NetBSD ...

includes ddb which has a syntax is similar to

References

{{Reflist, 30em Debuggers Operating system kernels