I have written a built-in kernel debugger
for the Linux operating system on Intel 32-bit Architecture platforms.
It is being made available for general use and abuse under the standard linux
licensing terms (see ./COPYING in the linux source distribution).
The debugger is part of the linux kernel and provides a means of examining
kernel memory and data structures while the system is operational.
Additional commands may be easily added to format and display essential
system data structures given an identifier or address of the data
structure. Current command set allows complete control of kernel
operations including single-stepping a processor, stopping upon
execution of a specific instruction, stopping upon access (or
modification) of a specific virtual memory location, stopping upon
access to a register in the input-output address space, stack
tracebacks for the current active task as well as for all other tasks
(by process id), instruction disassembly, et. al.
To use the kernel debugger, unzip the patch found at
http://reality.sgi.com/slurn_engr/
and apply the patch as normal to your linux 2.2.3 or 2.2.4 source tree
(it hasn't been tested yet with 2.2.5). Configure the new kernel
ensuring that the CONFIG_KDB and CONFIG_KDB_FRAMEPTR configuration
options are enabled (via xconfig, menuconfig, oldconfig or config make
options).
Version 0.1 of the built-in kernel debugger for Linux provides the
following features:
Instruction Breakpoints
Data Access Breakpoints
Single Instruction Execution
Stack tracebacks
Stack traceback for arbitrary processes
Ability to switch cpus in SMP system
Memory examination and modification
Instruction disassembly
Access to static and global symbols by name
Register access and modification
After applying the kernel debugger patch to a 2.2.3 or 2.2.4
source tree and recompiling, one can enter the debugger in the
following ways:
An ooops will cause the debugger to be invoked automatically
Likewise a data access fault in kernel mode
Using the 'kdb' flag on the lilo command line
Using the 'pause' key
----
Let me know what you think at slurn@engr.sgi.com
scott lurndal
silicon graphics, inc.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/