Re: 2.6.15-mm1 - locks solid when starting KDE (EDAC errors)

[Dave Jones <davej@redhat.com>]

On Sat, Jan 07, 2006 at 03:51:48AM +0100, Jesper Juhl wrote:

 > Ok, this is with a pristine 2.6.15-mm1 + Dave's oops-pausing-patch
 > Captured by switching to tty1 just after logging in via kdm.
 > A *lot* of info still scrolls down when the problem hits before Daves
 > patch stops it at a BUG dump, it scrolls by too fast for me to see
 > what it is, but I guess it must be warning/error messages other than
 > Oops's or BUG()'s ???
 > 
 > Anyway, here's the entire contents of my screen after Daves patch
 > stops the output - again written down by hand and then typed in from
 > my handwritten notes, so there may be typos, but I've tried to be
 > accurate.
 > 
 > 
 > 050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 090: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 0a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 > 0b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

My first thought was 'slab poison', but you don't have slab debugging turned on.
Randy's followup to my patch: http://lkml.org/lkml/2006/1/5/15
had another trick that may be useful. It'll slow down printk's
to a point where you might be able to see what happened.

another trick may be to just add a for (;;) into the BUG macro.

 > ------------{ cut here ]------------
 > kernel BUG at include/linux/list.h:166!
 > invalid opcode: 0000 [#1]
 > PREEMPT SMP
 > Last sysfs file: /class/vc/vcsa2/dev
 > Modules linked in: snd_seq_oss snd_seq_midi_event snd_seq snd_pcm_oss
 > snd_mixer_oss uhci_hcd usbcore snd_emu10k1 snd_rawmidi snd_ac97_codec
 > snd_ac97_bus snd_pcm snd_seq_device snd_timer snd_page_alloc
 > snd_util_mem snd_hwdep snd agpgart
 > CPU:    0
 > EIP:    0060:[<c01475f5>]    Tainted: G    B VLI

Hmm, you had hit bad_page(), so that may be a more useful place
to add a pause.

		Dave