Subject: Re: Random crashes with 2.6.27-rc3 on PPC

From: [email-masked] (Arnaud Ebalard)
Date: Sat, 23 Aug 2008 18:58:02 +0200

Hi,

Michael Buesch <[email-masked]> writes:

> I am seeing random kernel and userland application
> crashes on a Powerbook running a 2.6.27-rc3 based kernel
> (wireless-testing.git). 
>
> The crashes did recently appear. It might be the case that they were
> introduced with the merge of 2.6.27-rc1 into wireless-testing.
> I'm not sure on that one, however. Just a guess. I still need to
> do more testing (also on vanilla upstream kernels).
>
> The crashes are completely random and they look like bad hardware.
> However I cannot reproduce on 2.6.25.9 (That's a kernel I still had
> installed, so I tried that one). So it most likely is _not_ caused
> by faulty hardware.
>
> The crashes are hard to reproduce, and happen about every 20 minutes
> when compiling a kernel tree. (gcc segfaults). Sometimes the kernel
> oopses in random places with pointer dereference faults.

Exact same thing here on a PB 12" (not a ppc64, but ppc32). It was not
on a wireless-testing.git but on a recent net-2.6 or 2.6.27-rc3 (I do
not remember precisely). I thought it was a thermal issue and did not
spend time on it because of another regression I bisected (sysctl+IPv6)
that version useless for me.

> Is this a known issue?

Now it is ;-)

> I'm going to bisect this one, but it will take a lot of time, as
> reproducing takes about 20 minutes. So that's about an hour for one
> test round.

Thanks for doing that.

Cheers,

a+