Hi eric,
I once wrote Andrea Arcangeli on how to start kernel hacking.
Basically he told me to start by reading the code.
And looking at the current linux-kernel group, it would seem that
they follow the "IBM" method of solving bugs...that is to read the
code, understand what's happening and then make a fix. Quite well
and good, if you wrote the code... There is another method which I
call the "Microsoft" method; it assumes that you don't have to know
how the whole system works, just use a debugger to localize the
problem and then analyze the state (variables, flow, etc.) to fix the
problem. I think there must be a need for both styles to fix a system.
Anyway, the biggest problem with debugging a kernel is concurrency.
The kernel is not just one program with a single entry/exit point;
it is constantly juggling a lot of running processes. Setting a
breakpoint (to check the state of your new code) would cause a
lot of processes to stop (i.e. no mouse response since the mouse
input cannot be processed, etc.)
But there has been some efforts to allow for safe debugging:
- kgdb patches for the kernel
- http://lwn.net/2000/0914/a/ko-debugger.php3
- http://oss.sgi.com/projects/kgdb/
The idea here is to patch the "live" kernel for GDB.
This enables you to set breakpoints and do step-tracing over
the code. This works best if you run GDB on another machine
and it connects to the target machine via a serial link.
This is also similar to the NuMega Remote Debugger or
TurboDebugger for Microsoft Windows.
- User Mode Kernel
- http://user-mode-linux.sourceforge.net/
This allows you to create your own "vmlinux" program
that runs in user-mode (just like any other program).
It should allow you to gdb with no problems (I think)
I would like to get:
- Understanding the Linux Kernel, O'Reilly 2000
- Linux Device Drivers, 2nd Ed. O'Reilly 2001
- UNIX Systems For Modern Architectures, Addison-Wesley, 1994
- outdated but great intro on SMP concepts such as spinlocks
Of course, I also would like to hear actual kernel-hackers debug
the code...
Ambo
eric pareja wrote:
>
> Hello Juan et Alice,
>
> I'm curious who on the list is into serious kernel hacking, or even just
> interested in working on parts of the kernel? I know there are
> existing mailing lists elsewhere that deal with the kernel, but the
> traffic is sometimes way too heavy. If there's an interest, maybe we can
> have a small list for discussions amongst Filipinos who want to get a grip
> of Linux kernel internals and perhaps do a little work on it?
>
> As an aside, I'm scouting around for the Coriolis book on the Linux kernel
> with commentary. The last time I saw it was at Macromind in Megamall but
> it was quickly sold out, the next time I visited, they no longer had
> copies.
>
> xen
>
> ___ eric pareja ([EMAIL PROTECTED]) ~-=[O]=-~ Here, have a clue. Get the picture.
> \@/ PGP key at http://gra.ph/~xenos/xenos.pgp <|PLUG|> http://gra.ph
> v "Even the smallest person can change the course of the future."
> - Lady Galadriel in J.R.R. Tolkien's "The Lord of the Rings"
>
> _
> Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph
> To leave: send "unsubscribe" in the body to [EMAIL PROTECTED]
>
> To subscribe to the Linux Newbies' List: send "subscribe" in the body to
>[EMAIL PROTECTED]
_
Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph
To leave: send "unsubscribe" in the body to [EMAIL PROTECTED]
To subscribe to the Linux Newbies' List: send "subscribe" in the body to
[EMAIL PROTECTED]
