fs oops debuggable in 2.6 with one one machine

fs oops debuggable in 2.6 with one one machine

[Pat LaVarre]

Anybody yet work out in detail how to debug oops in filesystems without
connecting a second machine?

I haven't yet made the "more zeroes read back than appended" oops of
udf.ko reliably repeatable, but presuming eventually I do, then my next
hope is to capture the dmesg leading up to the oops.

I followed the web trail:

http://marc.theaimsgroup.com/?l=kernelnewbies&b=200310
http://marc.theaimsgroup.com/?l=kernelnewbies&m=106680564215479
http://kniggit.net/wwol26.html

I found:

---

Virtualizing Linux

One of the most interesting new features in Linux 2.6 is its inclusion
of a "user-mode" architecture. This is essentially a port (like to a
different hardware family) of Linux to itself, allowing for a completely
virtualized Linux-on-Linux environment to be run. The new instance of
Linux runs as if it was a normal application. "Inside" the application,
you can configure fake network interfaces, filesystems, and other
devices through special drivers which communicate up to the host copy of
Linux in a secure way. This has proved quite useful, both for
development purposes (profiling, etc.) as well as for security analysis
and honeypots. While most users will never need this kind of support, it
is an incredibly "cool" feature to have running on your box. (Impress
your friends!)

---

Pat LaVarre

Re: fs oops debuggable in 2.6 with one one machine

[Jan Hudec]

On Wed, Oct 22, 2003 at 06:44:56 -0600, Pat LaVarre wrote:
> Anybody yet work out in detail how to debug oops in filesystems without
> connecting a second machine?

Yes, you can use the user-mode linux. Project homepage is
user-mode-linux.sourceforge.net.

All code of user-mode linux except arch specific parts is the same as on
normal kernel, so chances are high, that this will be reproducible.

It is fully debuggable with gdb. However, gdb does not seem to
understand output from gcc-3 correctly, so gcc-2.95 (or using -gstabs
option to gcc) is needed.

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						 Jan 'Bulb' Hudec <bulb@ucw.cz>