insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Harald Welte]

Hi!

I was trying to get a recent linuxppc-2.5 (or benh) kernel running on my
G4 Titanium Powerbook IV, and it wouldn't even finish to boot.

After some debugging, I found it was always crashing when sshd started.
That in turn was, because the kernel tried to autoload the ipv6.ko
module for sshd to listen at ::.

booting into single user mode and manually issuing 'insmod ipv6' shows
exactly the same behaviour:  A full freeze, no more cursor at the
console, but still responds to pings from the network.

Firing up xmon seems to reveal it is looping somewhere:

pc is always between (count_relocs+0x34) and (count_relocs+0x40),
backtrace:
(t get_plt_size+0x60)
(T module_frob_arch_sections+0xdc)
(t load_module+0x474)
(t sys_init_module+0x78)
(T ret_from_syscall+0x0)

btw: The system is running a current debian 'testing'.

Is this a known issue? Any ideas?

--
- Harald Welte <laforge@gnumonks.org>               http://www.gnumonks.org/
============================================================================
Programming is like sex: One mistake and you have to support it your lifetime

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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Benjamin Herrenschmidt]

On Fri, 2003-11-21 at 07:12, Harald Welte wrote:
> Hi!
>
> I was trying to get a recent linuxppc-2.5 (or benh) kernel running on my
> G4 Titanium Powerbook IV, and it wouldn't even finish to boot.

Interesting. Same machine here and I use 2.6 everyday :)

> After some debugging, I found it was always crashing when sshd started.
> That in turn was, because the kernel tried to autoload the ipv6.ko
> module for sshd to listen at ::.

Ah...

> booting into single user mode and manually issuing 'insmod ipv6' shows
> exactly the same behaviour:  A full freeze, no more cursor at the
> console, but still responds to pings from the network.

What does your .config looks like ? nothing scary like CONFIG_PREEMPT ?

I'll do some tests here...

Ben.


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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Harald Welte]

On Fri, Nov 21, 2003 at 02:54:38PM +1100, Benjamin Herrenschmidt wrote:

> Interesting. Same machine here and I use 2.6 everyday :)

The problem seems to be gcc-related.  Debian testing seems to have
installed gcc-3.3.2 (yes, maybe not the best compiler for a kernel
anyway) per default.

compiling the same kernel with gcc-2.95 results in a working ipv6
module.

any idea how to submit such a bug to the gcc people?

--
- Harald Welte <laforge@gnumonks.org>               http://www.gnumonks.org/
============================================================================
Programming is like sex: One mistake and you have to support it your lifetime

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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Harald Welte]

On Fri, Nov 21, 2003 at 04:32:52PM +0100, Harald Welte wrote:
>
> On Fri, Nov 21, 2003 at 02:54:38PM +1100, Benjamin Herrenschmidt wrote:
>
> > Interesting. Same machine here and I use 2.6 everyday :)
>
> The problem seems to be gcc-related. Debian testing seems to have
> installed gcc-3.3.2 (yes, maybe not the best compiler for a kernel
> anyway) per default.
>
> compiling the same kernel with gcc-2.95 results in a working ipv6
> module.

I did some more testing:

Compiles with gcc-3.3.2 and gcc-3.2.3 result in a broken kernel,
gcc-3.0.4 and gcc-2.95.4 work fine.

--
- Harald Welte <laforge@gnumonks.org>               http://www.gnumonks.org/
============================================================================
Programming is like sex: One mistake and you have to support it your lifetime

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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Michel Dänzer]

On Sun, 2003-11-30 at 16:55, Harald Welte wrote:
> On Fri, Nov 21, 2003 at 04:32:52PM +0100, Harald Welte wrote:
> >
> > On Fri, Nov 21, 2003 at 02:54:38PM +1100, Benjamin Herrenschmidt wrote:
> >
> > > Interesting. Same machine here and I use 2.6 everyday :)
> >
> > The problem seems to be gcc-related. Debian testing seems to have
> > installed gcc-3.3.2 (yes, maybe not the best compiler for a kernel
> > anyway) per default.
> >
> > compiling the same kernel with gcc-2.95 results in a working ipv6
> > module.
>
> I did some more testing:
>
> Compiles with gcc-3.3.2 and gcc-3.2.3 result in a broken kernel,
> gcc-3.0.4 and gcc-2.95.4 work fine.

I've been running Ben's tree built with gcc-3.3 for a while (since
test7-ish) without problems:

daenzer@thor|16:55:01> cat /proc/version                               ~
Linux version 2.6.0-test11-benh (daenzer@thor) (gcc version 3.3.2
(Debian)) #1 Sat Nov 29 14:07:02 CET 2003
daenzer@thor|16:55:43> lsmod|grep ip                                   ~
ipv6                  290072  15


What version of binutils do you have? Current from testing here.


--
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Software libre enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer

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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Franz Sirl]

At 16:55 30.11.2003, Harald Welte wrote:

>On Fri, Nov 21, 2003 at 04:32:52PM +0100, Harald Welte wrote:
> >
> > On Fri, Nov 21, 2003 at 02:54:38PM +1100, Benjamin Herrenschmidt wrote:
> >
> > > Interesting. Same machine here and I use 2.6 everyday :)
> >
> > The problem seems to be gcc-related. Debian testing seems to have
> > installed gcc-3.3.2 (yes, maybe not the best compiler for a kernel
> > anyway) per default.
> >
> > compiling the same kernel with gcc-2.95 results in a working ipv6
> > module.
>
>I did some more testing:
>
>Compiles with gcc-3.3.2 and gcc-3.2.3 result in a broken kernel,
>gcc-3.0.4 and gcc-2.95.4 work fine.

Works fine for me with bk linuxppc-2.5 (test9/10/11), gcc-3.3.2 and
binutils-2.14.90.0.6. gcc is built from the gcc-3_3-rhl-branch, binutils as
in fedora development.

Franz.


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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Harald Welte]

On Tue, Dec 02, 2003 at 04:59:39PM +0100, Michel Dänzer wrote:
>
> On Sun, 2003-11-30 at 16:55, Harald Welte wrote:
> > On Fri, Nov 21, 2003 at 04:32:52PM +0100, Harald Welte wrote:
> > >
> > > On Fri, Nov 21, 2003 at 02:54:38PM +1100, Benjamin Herrenschmidt wrote:
> > >
> > > > Interesting. Same machine here and I use 2.6 everyday :)
> > >
> > > The problem seems to be gcc-related. Debian testing seems to have
> > > installed gcc-3.3.2 (yes, maybe not the best compiler for a kernel
> > > anyway) per default.
> > >
> > > compiling the same kernel with gcc-2.95 results in a working ipv6
> > > module.
> >
> > I did some more testing:
> >
> > Compiles with gcc-3.3.2 and gcc-3.2.3 result in a broken kernel,
> > gcc-3.0.4 and gcc-2.95.4 work fine.
>
> I've been running Ben's tree built with gcc-3.3 for a while (since
> test7-ish) without problems:
>
> What version of binutils do you have? Current from testing here.

the same here.  I can now even confirm the same problem on a different
machine, a dual G4 450, running debian testing.

The actual problem seems not to be an infinite loop, but rather a very
long loop.   IF you wait long enough, it will eventually work.  A
significant delay (i.e. assumed long loop) is also observed while
loading any module.  Something like 10 - 15 seconds for every module
that I'm loading during startup (ipv6, tulip, dmasound_pmac, ...)

The machine is completely frozen during that loop, not even the cursor
is blinking anymore.

compiling the kernel with gcc 2.95 or 3.0 removes those symptoms.

> --
> Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
--
- Harald Welte <laforge@gnumonks.org>               http://www.gnumonks.org/
============================================================================
Programming is like sex: One mistake and you have to support it your lifetime

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Re: insmod ipv6 freezes current linuxppc-2.5 and 2.5-benh

[Michel Dänzer]

On Sat, 2003-12-13 at 10:03, Harald Welte wrote:
>
> The actual problem seems not to be an infinite loop, but rather a very
> long loop.   IF you wait long enough, it will eventually work.  A
> significant delay (i.e. assumed long loop) is also observed while
> loading any module.  Something like 10 - 15 seconds for every module
> that I'm loading during startup (ipv6, tulip, dmasound_pmac, ...)
>
> The machine is completely frozen during that loop, not even the cursor
> is blinking anymore.
>
> compiling the kernel with gcc 2.95 or 3.0 removes those symptoms.

As I'm not seeing this, you may want to compare your .config to mine,
which is http://penguinppc.org/~daenzer/config-2.6.0-test11-benh


--
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Software libre enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer

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