systematic panic on an SMP machine for 5.1-Release

Terry Lambert tlambert2 at
Wed Jul 9 01:13:34 PDT 2003

Kevin Oberman wrote:
> > PS : is this an indication of bug in the p-III or in the chipset ?
> > (ISTR these options could be used to get around unnamed errata of
> > the p-IV)
> Terry has never been specific (due to non-disclosure), but adding
> options DISABLE_PSE to the kernel of my P4 system results in a solid
> crash when the apm driver probes. (This could be an apm(4) problem, as
> well.)

This is really strange; I'd like to try and help debug this one
(off-list, so we don't bother anyone else with a lot of back and
forth).  There's actually nothing I could think of that could
cause this, unless it's the BIOS accessing what it thinks is
a linear access to low-core memory, and it not having a page
mapping without the 4M page mapped.  If this is happening, it's
most likely spamming something on you without DISABLE_PSE, and
you just don't know it because it's not important.

I could give you a snippet of code, or walk you through writing
one, that would make sure to establish 4K page mappings for the
whole area that's normally covered by a 4M mapping; if this was
able to fix the problem, then it's likely you are being spammed
and that your BIOS is doing Very Bad Things(tm).

My gut feeling on this is that the APM is spamming memory,
though, and you won't be happy with a workaround that doesn't
save you from this.

Is there any way you could try ACPI on this board, instead of
using APM?  Or see if the vendor has a BIOS update (making sure
you keep an old copy, just in case you want to go back)?

-- Terry

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