ACPI panic
Stefan Farfeleder
stefanf at FreeBSD.org
Wed Nov 21 10:48:47 UTC 2012
On Wed, Nov 21, 2012 at 12:55:36AM +0200, Andriy Gapon wrote:
> on 20/11/2012 12:35 Stefan Farfeleder said the following:
> > Hi,
> >
> > today I got the following panic on booting. The error seems to be some
> > kind of race condition, as the same kernel booted fine before and
> > afterwards. This is current, r243234.
> >
> > Any additional information required to debug/fix this?
> [snip]
>
> This indeed looks like a heisenbug that happens to FreeBSD users now and then
> (google for AcpiOsAcquireObject panic).
> I am trying a verify a certain theory... just on the chance that this issue
> happens again, could you please try the following debugging patch?
>
> Index: sys/contrib/dev/acpica/components/utilities/utdelete.c
> ===================================================================
> --- sys/contrib/dev/acpica/components/utilities/utdelete.c (revision 243265)
> +++ sys/contrib/dev/acpica/components/utilities/utdelete.c (working copy)
> @@ -441,7 +441,7 @@
> "Obj %p Refs=%X, can't decrement! (Set to 0)\n",
> Object, NewCount));
>
> - NewCount = 0;
> + NewCount = *(volatile UINT16*)NULL;
> }
> else
> {
>
>
> I hope that this compiles. The point is to induce a panic sooner rather than later.
Thanks. I've applied this and will report back if it triggers a panic.
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