How to use KDB in Linux?

To enter kdb using a breakpoint, first invoke kdb using the Magic SysRq key (see above), then set a breakpoint. Then type ‘go’ to continue execution. When the breakpoint is hit, the debugger shell will appear. In the example that follows, items in italics are commands typed by a user.

How kgdb works?

Kgdb supports using the gdb serial protocol to send console messages to the debugger when the debugger is connected and running. There are two ways to activate this feature. If you do this after you configure the kgdb I/O driver, the setting will not take effect until the next point the I/O is reconfigured.

What is KDB in AIX?

The KDB kernel debugger and the kdb command are useful for debugging device drivers, kernel extensions, and the kernel itself. Although they appear similar, the KDB kernel debugger and the kdb command are two separate tools: KDB KERNEL DEBUGGER.

What is KDB in Linux?

The Linux kernel debugger (KDB) allows you to debug the Linux kernel. This aptly named tool is essentially a patch to the kernel code that lets hackers access kernel memory and data structures.

How do I get into KDB?

Enter the KDB kernel debugger using one of the following procedures:

  1. On a tty keyboard, press the Ctrl+4 key sequence for IBM® 3151 terminals or the Ctrl+\ key sequence for BQ 303, BQ 310C, and WYSE 50 terminals.
  2. On other keyboards, press the Ctrl+Alt+Numpad4 key sequence.

What is GDB tool in Linux?

GNU Debugger, also known as gdb, allows us to sneak through the code while it executes or what a program was trying to do at the moment before it crashed. GDB basically helps us to do four main things to catch flaws in the source code. Start the program, specifying arguments that may affect the general behavior.

What is a GDB command file?

A command file for GDB is a text file made of lines that are GDB commands. Comments (lines starting with # ) may also be included. An empty line in a command file does nothing; it does not mean to repeat the last command, as it would from the terminal.

What is the KDB command in Linux?

The kdb command interprets and formats control structures in the system and provides miscellaneous functions for examining a dump. The SystemImageFile parameter specifies the file that contains the system image. The value can indicate a system dump, the name of a dump device, or the /dev/pmem special file.

What is the kernelfile parameter in kdb?

The KernelFile parameter specifies the AIX® kernel that kdb will use to resolve kernel symbol definitions. A kernel file must be available. When examining a system dump it is imperative that the kernel file be the same as the kernel that was used to take the system dump. The default for the KernelFile is /unix.

How do I Grep a specific KDB command?

kdb includes a grep-like capability, which provides the ability to filter command results using a pattern. To use this, type the regular command, and at the end of the line add ‘| grep ‘, where pattern is the pattern to match. To see online help for this feature, type ‘grephelp’ at the kdb shell prompt.

What does a leading dash in a KDB command mean?

A leading dash indicates to ignore any errors processing a command. In the kernel source, you can place commands in the file ‘kdb_cmds’. These commands will be executed by kdb on it’s initialization. By default, a few command sets are declared: ‘dumpcommon’, ‘dumpall’, and ‘dumpcpu’.