2009-03-13 20:07:28

by Nico Schottelius

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Subject: Strange reboots on 2.6.29-rc6-wl

Hello!

I've two Lenovo X200 here, same config and same kernel version
(2.6.29-rc7-wl-ikn, from wireless-testing, v2.6.29-rc7-17155-g2f7ab92).

One reboots after half a second after displaying a message Probing for edd
(or similar). I tried with and without edd=off, no changes.

The same happens with v2.6.29-rc7-32930-g5434dd7 (iwlwifi-2.6).

Anyone an idea, what maybe the reason for that behaviour?

Nico

--
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2009-03-13 20:45:44

by John W. Linville

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Subject: Re: Strange reboots on 2.6.29-rc6-wl

On Fri, Mar 13, 2009 at 09:06:57PM +0100, Nico Schottelius wrote:
> Hello!
>
> I've two Lenovo X200 here, same config and same kernel version
> (2.6.29-rc7-wl-ikn, from wireless-testing, v2.6.29-rc7-17155-g2f7ab92).
>
> One reboots after half a second after displaying a message Probing for edd
> (or similar). I tried with and without edd=off, no changes.
>
> The same happens with v2.6.29-rc7-32930-g5434dd7 (iwlwifi-2.6).
>
> Anyone an idea, what maybe the reason for that behaviour?

No clue. But since you clearly are comfortable with git and building
your own kernels, perhaps you can use git bisect to suggest which
commit is broken? :-)

John
--
John W. Linville Someday the world will need a hero, and you
[email protected] might be all we have. Be ready.

Subject: Re: Strange reboots on 2.6.29-rc6-wl

John W. Linville [Fri, Mar 13, 2009 at 04:41:01PM -0400]:
> On Fri, Mar 13, 2009 at 09:06:57PM +0100, Nico Schottelius wrote:
> > Hello!
> >
> > I've two Lenovo X200 here, same config and same kernel version
> > (2.6.29-rc7-wl-ikn, from wireless-testing, v2.6.29-rc7-17155-g2f7ab92).
> >
> > One reboots after half a second after displaying a message Probing for edd
> > (or similar). I tried with and without edd=off, no changes.
> >
> > The same happens with v2.6.29-rc7-32930-g5434dd7 (iwlwifi-2.6).
> >
> > Anyone an idea, what maybe the reason for that behaviour?
>
> No clue. But since you clearly are comfortable with git and building
> your own kernels, perhaps you can use git bisect to suggest which
> commit is broken? :-)

It seems there's something different broken, all newly built
kernels are instantly rebooting. All are displaying the
"edd=off" warning message.

The gcc version is slightly different (4.1.3 vs. 4.3.3, both Debian),
but I'm already running next-20090306 compiled with this compiler.

Has anyone a clue on howto debug the build environment or
debugging the kernel before it's getting booted?

Nico

--
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2009-03-17 14:58:19

by Sitsofe Wheeler

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Subject: Re: Strange reboots on 2.6.29-rc6-wl

On Tue, Mar 17, 2009 at 08:54:24AM +0100, Nico -telmich- Schottelius wrote:
>
> Has anyone a clue on howto debug the build environment or
> debugging the kernel before it's getting booted?

If you have a serial console you can probably get output on that. If you
have flipped EMBEDDED to Y then you might also have to enable
EARLY_PRINTK. Another trick might be to turn set
BOOT_PRINTK_DELAY (Kernel hacking -> Delay each boot printk message by N
milliseconds) to something like 2000 and see if you can read/catch the
messages before the kernel reboots...

Failing that start a git bisection (
http://www.kernel.org/doc/local/git-quick.html#bisect or
http://www.stardust.webpages.pl/files/handbook/handbook-en-0.3-rc1.pdf )
from the last good kernel...

--
Sitsofe | http://sucs.org/~sits/

Subject: Re: Strange reboots on 2.6.29-rc6-wl

Sitsofe Wheeler [Tue, Mar 17, 2009 at 02:57:53PM +0000]:
> On Tue, Mar 17, 2009 at 08:54:24AM +0100, Nico -telmich- Schottelius wrote:
> >
> > Has anyone a clue on howto debug the build environment or
> > debugging the kernel before it's getting booted?
>
> If you have a serial console you can probably get output on that.

There's no native serial port on the machine :-/

> If you have flipped EMBEDDED to Y then you might also have to enable
> EARLY_PRINTK. Another trick might be to turn set
> BOOT_PRINTK_DELAY (Kernel hacking -> Delay each boot printk message by N
> milliseconds) to something like 2000 and see if you can read/catch the
> messages before the kernel reboots...

I've EARLY_PRINTK set, but other than the edd probing message
I don't see anything.

> Failing that start a git bisection (
> http://www.kernel.org/doc/local/git-quick.html#bisect or
> http://www.stardust.webpages.pl/files/handbook/handbook-en-0.3-rc1.pdf )
> from the last good kernel...

I really don't think that it's the kernel's fault, because _all_
new versions I compile instantly reboot.

Last one I tried was v2.6.29-rc8-241-g65c2449 (linux-2.6).
Isn't there some flag to enable step by step execution (like in gdb)?

Or is somebody else using Debian squeeze with latest updates?

Sincerly,

Nico

--
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2009-03-21 13:04:20

by Sitsofe Wheeler

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Subject: Re: Strange reboots on 2.6.29-rc6-wl

On Fri, Mar 20, 2009 at 11:21:07AM +0100, Nico -telmich- Schottelius wrote:
> Sitsofe Wheeler [Tue, Mar 17, 2009 at 02:57:53PM +0000]:
> > On Tue, Mar 17, 2009 at 08:54:24AM +0100, Nico -telmich- Schottelius wrote:
> > >
> > > Has anyone a clue on howto debug the build environment or
> > > debugging the kernel before it's getting booted?
> >
> > If you have a serial console you can probably get output on that.
>
> There's no native serial port on the machine :-/
>
> > If you have flipped EMBEDDED to Y then you might also have to enable
> > EARLY_PRINTK. Another trick might be to turn set
> > BOOT_PRINTK_DELAY (Kernel hacking -> Delay each boot printk message by N
> > milliseconds) to something like 2000 and see if you can read/catch the
> > messages before the kernel reboots...
>
> I've EARLY_PRINTK set, but other than the edd probing message
> I don't see anything.

What about when you set BOOT_PRINTK_DELAY to a value high enough to
cause pauses - do you see more messages? Additionally are booting your
kernel without the quiet option? Have you checked to make sure the
kernel isn't set to reboot on oops/panic etc? Are you using any binary
drivers?

> > Failing that start a git bisection (
> > http://www.kernel.org/doc/local/git-quick.html#bisect or
> > http://www.stardust.webpages.pl/files/handbook/handbook-en-0.3-rc1.pdf )
> > from the last good kernel...
>
> I really don't think that it's the kernel's fault, because _all_
> new versions I compile instantly reboot.

So even a freshly compiled 2.6.27 and 2.6.28 reboot instantly?! If even
old kernels that worked suddently don't work that hints strongly at
hardware errors or a duff compiler toolchain...

You can also make the kernel spit out decompression error messages by
enabling CONFIG_X86_VERBOSE_BOOTUP . I guess it would also be wise to
make sure CONFIG_DOUBLEFAULT is also set. Are you sure nothing else has
changed though? Have you enabled some kernel option that was not set
before? Have you changed any BIOS settings recently?

> Last one I tried was v2.6.29-rc8-241-g65c2449 (linux-2.6).
> Isn't there some flag to enable step by step execution (like in gdb)?

I don't think I undrstand what you mean - the kernel isn't a debugger...
If you are running a User Mode Linux kernel or running inside QEMU etc.
then you can do what you describe because your "machine" is a program
but I think the only way to do that with real hardware is to learn how
to use KGDB ( http://kgdb.sourceforge.net ) and have another machine to
hand. I suppose you could also sprinkle beep patches/debug printks about
the place to see just how far it gets before it reboots...

--
Sitsofe | http://sucs.org/~sits/

Subject: Re: [ipw3945-devel] Strange reboots on 2.6.29-rc6-wl


Nico Schottelius [Fri, Mar 13, 2009 at 09:06:57PM +0100]:
>
> I've two Lenovo X200 here, same config and same kernel version
> (2.6.29-rc7-wl-ikn, from wireless-testing, v2.6.29-rc7-17155-g2f7ab92).
>
> One reboots after half a second after displaying a message Probing for edd
> (or similar). I tried with and without edd=off, no changes.
>
> The same happens with v2.6.29-rc7-32930-g5434dd7 (iwlwifi-2.6).

It works again with 2.6.29 (linux-2.6) and next-20090324 (which
is otherwise broken)!

Will test iwlwifi & wireless-testing in the next days.

So it was definitely a kernel issue and not userspace.

Nico

--
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http://nico.schottelius.org/documentations/foss/the-term-foss/

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