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Date: Sat, 22 Dec 2012 13:11:09 +0200
From: Andriy Gapon <avg@FreeBSD.org>
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To: Hans Petter Selasky <hselasky@c2i.net>
Subject: double fault [Was: clang compiled kernel panic when mounting zfs
 root on i386]
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on 21/12/2012 18:38 Hans Petter Selasky said the following:
> I've built a 10-current i386 kernel as of today, and I see double fault when 
> USB audio is allocating memory. Anyone knows why?
> 
> kdb_enter()
> vpanic()
> panic()
> dblfault_handler()
> vm_map_lookup()
> vm_fault_hold()
> vm_fault()
> vm_fault_wire()
> vm_map_wire()
> kmem_alloc_attr(xxx, 0x4000,2,0,0xffffffff)
> bus_dmamem_alloc()
> usb_pc_alloc_mem()

I suspect that this double fault may have nothing to do with the thread to which
you followed up.

You need to obtain full debug information to answer your question.

-- 
Andriy Gapon