zfs kernel panic, known incompatibilities with clang & CPUTYPE/COPTFLAGS?

Peter Wemm peter at wemm.org
Wed Jun 12 22:11:00 UTC 2013

On Wed, Jun 12, 2013 at 1:39 PM, Dimitry Andric <dim at freebsd.org> wrote:
> On Jun 12, 2013, at 22:30, Alexander Leidinger <Alexander at Leidinger.net> wrote:
>> I try to update from a pre-clang world (r242511M) to "now" (r251618M).
>> The resulting kernel boots, but while starting some jails (with ezjail
>> from ports, so fairly late in the boot process) I get a kernel panic
>> (IIRC zfs trying to access page 0).
> If you are running on i386, it might be a stack overflow?  Try
> increasing the stack a little, it might help in that case.

For i386 I'd be more inclined to suspect KVA exhaustion.

For non-PAE, as a shot in the dark, increase
options KVA_PAGES=384
.. the default is 256 for PAE.  that increases kernel KVA from 1GB to 1.5GB.

For a PAE system, this number is multipled by 2, so a corresponding
change is 512 -> 768.

This is just a shot in the dark.  If this is amd64, then never mind,
KVA_PAGES is meaningless there.
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
On IRC, talking about C++:
<BigKnife> I think that it is a good thing I will never meet Bjarne on a street
<BigKnife> cause really, I don't want to end up in prison or anything

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