Kernel debugger

A kernel debugger is a debugger present in some kernels 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 gdb, running on another machine, sending commands to the stub over a serial line 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 family includes a kernel debugger named KD,^[1] which can act as a local debugger with limited capabilities (reading and writing kernel memory, but not setting breakpoints)^[2] and can attach to a remote machine over a serial line, IEEE 1394 connection, USB 2.0 or USB 3.0 connection.^[3] The WinDbg GUI debugger can also be used to debug kernels on local and remote machines.
• BeOS
• DragonFly BSD
• Linux kernel; No kernel debugger was included in the mainline Linux tree prior to version 2.6.26-rc1 because Linus Torvalds didn't want a kernel debugger in the kernel.^[4][5]
  • KDB (local)^[6]
  • KGDB (remote)
  • MDB (local/remote)^[7][8][9]
• NetBSD (DDB for local, KGDB for remote)
• OS X,^[10] Darwin which runs the XNU kernel using the Mach component

References

1. "KD". Retrieved 2011-01-25.
2. "Performing Local Kernel Debugging". Retrieved 2011-01-25.
3. "Windows Debugging". Retrieved 2013-05-22.
4. "LWN.net". Retrieved 2008-05-29.
5. Torvalds, Linus (3 May 2008). "Linux 2.6.26-rc1". LWN. Retrieved 9 March 2015.
6. Nellitheertha, Hariprasad. "Inside the Linux kernel debugger". Retrieved 2008-05-29.
7. "LWN Weekly Kernel News". 7 Sep 2008.
8. "MDB Github Website". 1 Jan 2016.
9. "LWN Weekly Kernel News". 28 June 2010.
10. Singh, Amit (December 2003). "XNU: The Kernel". What is Mac OS X?. Retrieved 2012-05-25. the built-in low-level kernel debugger, ddb, is part of XNU's Mach component, and so is kdp, a remote kernel debugging protocol implementation