User-mode Linux kernel port

On Tue, Mar 25, 2003 at 11:46:26PM -0600, Jason Bodnar wrote:
> When I try to run uml in debug mode as so:
> 
> $ linux ubd0=root_fs_toms1.7.205 debug
>
> Nothing happens. Isn't it supposed to pop up an xterm running gdb?

TT mode is, SKAS mode isn't. You are supposed to run SKAS mode with
debuging as:

$ gdb linux
(gdb) tty <sometty>
(gdb) run ubd0=root_fs_toms1.7.205

Where <sometty> is a tty with no session running. (there are hundreds of
ways to get one - an unused vc, xterm -hold -e tty (prints it's name and
remains open) ...). You wan't to do this, because otherwise umlinux
would get keyboard interrupts and they wouldn't make it to the debugger.

> --
> Jason Bodnar
> jason@...
> http://www.shakabuku.org
> 
> "You want free speech? Let's see you acknowledge a man whose words make
> your blood boil who is standing center stage advocating at the top of
> his lungs that which you would spend a lifetime opposing at the top of
> yours." -- President Andrew Shephard, "The American President"
> 
> 
> 
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-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@...>

On Wed, 26 Mar 2003 10:51:04 +0100, Jan Hudec wrote
> On Tue, Mar 25, 2003 at 11:46:26PM -0600, Jason Bodnar wrote:
> > When I try to run uml in debug mode as so:
> > 
> > $ linux ubd0=root_fs_toms1.7.205 debug
> >
> > Nothing happens. Isn't it supposed to pop up an xterm running gdb?
> 
> TT mode is, SKAS mode isn't. You are supposed to run SKAS mode with
> debuging as:

I have no idea if my kernel is running in TT or SKAS mode. According to the
website (http://user-mode-linux.sourceforge.net/skas.html) I should see some
sort of message checking for the SKAS3 patch. I don't see anything like that.
The only "Checking" I see is:

Checking for host processor cmov support...Yes
Checking for host processor xmm support...No
Checking that ptrace can change system call numbers...OK
Checking that host ptys support output SIGIO...Yes
Checking that host ptys support SIGIO on close...No, enabling workaround

I'm using the kernel rpm from the web site on Mandrake 9.0. with Kernel
2.4.19-16mdk.

--
Jason Bodnar
jason@...
http://www.shakabuku.org

"You want free speech? Let's see you acknowledge a man whose words make
your blood boil who is standing center stage advocating at the top of
his lungs that which you would spend a lifetime opposing at the top of
yours." -- President Andrew Shephard, "The American President"

On Wed, Mar 26, 2003 at 01:27:53PM -0600, Jason Bodnar wrote:
> On Wed, 26 Mar 2003 10:51:04 +0100, Jan Hudec wrote
> > On Tue, Mar 25, 2003 at 11:46:26PM -0600, Jason Bodnar wrote:
> > > When I try to run uml in debug mode as so:
> > > 
> > > $ linux ubd0=root_fs_toms1.7.205 debug
> > >
> > > Nothing happens. Isn't it supposed to pop up an xterm running gdb?
> > 
> > TT mode is, SKAS mode isn't. You are supposed to run SKAS mode with
> > debuging as:
> 
> I have no idea if my kernel is running in TT or SKAS mode. According to the
> website (http://user-mode-linux.sourceforge.net/skas.html) I should see some
> sort of message checking for the SKAS3 patch. I don't see anything like that.
> The only "Checking" I see is:
> 
> Checking for host processor cmov support...Yes
> Checking for host processor xmm support...No
> Checking that ptrace can change system call numbers...OK
> Checking that host ptys support output SIGIO...Yes
> Checking that host ptys support SIGIO on close...No, enabling workaround
>
> I'm using the kernel rpm from the web site on Mandrake 9.0. with Kernel
> 2.4.19-16mdk.

If you did not apply the skas3 patch, it can't use it...
You should state which version the _user mode linux_ is too (SKAS mode
works from somewhere around 2.4.19-20um).
If it really ran in skas mode, the _very first_ two lines it print would
read:
Checking for the skas3 patch in the host...found
Checking for /proc/mm...found
So no, it does not run in SKAS mode.

Then one more thing comes to mind. Check, that you have debugging
support compiled in.

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@...>

On Wed, 26 Mar 2003, Jason Bodnar wrote:

> I have no idea if my kernel is running in TT or SKAS mode. According to the
> website (http://user-mode-linux.sourceforge.net/skas.html) I should see some
> sort of message checking for the SKAS3 patch. I don't see anything like that.
> The only "Checking" I see is:

I've trashed my old mail messages, but when I run

/usr/bin/linux ncpus=4 mem=256M ubd0=root_fs ubd1=swap_fs eth0=ethertap,tap0,,192.168.1.254 con=null ssl=null devfs=nomount

on my Red Hat system I see

[mike@... gentoo]$ ./start
Checking for the skas3 patch in the host...found
Checking for /proc/mm...found
Kernel virtual memory size shrunk to 258998272 bytes
Linux version 2.4.20-mike-2um (mike@...) (gcc version 3.2 20020903 (Red Hat Linux 8.0 3.2-7)) #1 Tue Mar 25 20:20:53 EST 2003
[...]

way before the processor checks.

> I'm using the kernel rpm from the web site on Mandrake 9.0. with Kernel
> 2.4.19-16mdk.

I'm using Red Hat 8.0 (not the latest kernel which broke skas3 support) 
and Roger Binns module for skas3 support (provides /proc/mm on the host)

Hope this helps,

Mike

-- 
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mike@...                  | Fingerprint      0570 71CD 6790 7C28 3D60
http://www.exegenix.com/           |                  75D2 9EC4 C1C0 0599 13DA

On Wed, 26 Mar 2003, Jason Bodnar wrote:

> I have no idea if my kernel is running in TT or SKAS mode. According to the
> website (http://user-mode-linux.sourceforge.net/skas.html) I should see some
> sort of message checking for the SKAS3 patch. I don't see anything like that.
> The only "Checking" I see is:

Sorry for the 2nd follow up; I just noticed that in my UML I can see my 
mode in /proc/cpuinfo:

mike@... mike $ uname -a
Linux gentoo-uml.stok.co.uk 2.4.20-mike-2um #1 Tue Mar 25 20:20:53 EST 2003 i686 UML User Mode Linux GNU/Linux
mike@... mike $ cat /proc/cpuinfo
processor       : 0
vendor_id       : User Mode Linux
model name      : UML
mode            : skas
host            : Linux ratdog.stok.co.uk 2.4.18-26.8.0 #1 Mon Feb 24 10:21:42 EST 2003 i686
bogomips        : 1605.68

That was news to me :-)

Mike

-- 
mike@...                    |           The "`Stok' disclaimers" apply.
http://www.stok.co.uk/~mike/       | GPG PGP Key      1024D/059913DA 
mike@...                  | Fingerprint      0570 71CD 6790 7C28 3D60
http://www.exegenix.com/           |                  75D2 9EC4 C1C0 0599 13DA

On Wed, Mar 26, 2003 at 02:44:11PM -0500, Mike Stok wrote:
> On Wed, 26 Mar 2003, Jason Bodnar wrote:
> 
> > I have no idea if my kernel is running in TT or SKAS mode. According to the
> > website (http://user-mode-linux.sourceforge.net/skas.html) I should see some
> > sort of message checking for the SKAS3 patch. I don't see anything like that.
> > The only "Checking" I see is:
> 
> I've trashed my old mail messages, but when I run
> 
> /usr/bin/linux ncpus=4 mem=256M ubd0=root_fs ubd1=swap_fs eth0=ethertap,tap0,,192.168.1.254 con=null ssl=null devfs=nomount
> 
> on my Red Hat system I see
> 
> [mike@... gentoo]$ ./start

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

> Checking for the skas3 patch in the host...found
> Checking for /proc/mm...found

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Thus the important patch is in place, skas mode is enabled, thus it IS
SKAS MODE.

That means I was right and debug is not apropriate in your situation.
You need to simply start this all from gdb. You want to use gdb's tty
commad because gdb wouldn't see interrputs otherwise. You also want to
set handling of SIGUSR1, SIGTRAP and SIGSEGV to nostop noprint pass.

(I have some controling scripts to do the work. I think I have already
posted them, but I might post them again if someone is interested).

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@...>

Jason Bodnar wrote:

>I have no idea if my kernel is running in TT or SKAS mode. According to the
>website (http://user-mode-linux.sourceforge.net/skas.html) I should see some
>sort of message checking for the SKAS3 patch. I don't see anything like that.
>  
>
Sometimes the "checking for SKAS patch in host" message doesn't make it 
to my console until after I halt the UML.   Do you see anything when you 
shut down right after "System halted."?

-- 
Mark Ryan
Institute for Security Technology Studies
Dartmouth College
Key fingerprint = DDEB 70ED 289A A94B E918 4D61 D0D4 F89A B642 8960

Jan Hudec <bulb@...> writes:

[...]

> That means I was right and debug is not apropriate in your situation.
> You need to simply start this all from gdb. You want to use gdb's tty
> commad because gdb wouldn't see interrputs otherwise. You also want to
> set handling of SIGUSR1, SIGTRAP and SIGSEGV to nostop noprint pass.
>
> (I have some controling scripts to do the work. I think I have already
> posted them, but I might post them again if someone is interested).

I would find it useful to see these controlling scripts.  I couldn't
find the previous post you thought you had made anywhere in the
mailing list archives.
-- 
Benjamin