clang compiled kernel panic when mounting zfs root on i386

[sig6247]

On Fri, 30 Nov 2012 01:29:44 +0200, Konstantin Belousov <kostikbel at gmail.com> wrote:

> Please apply the patch below and obtain the backtrace of the double fault
> panic again. I will commit the patch later.

Thanks for the patch. 

WARNING: WITNESS option enabled, expect reduced performance.
Trying to mount root from zfs:zroot []...

Fatal double fault:
eip = 0xc0e93e07
esp = 0xc86bffbc
ebp = 0xc86c0032
cpuid = 1; apic id = 01
panic: double fault
cpuid = 1
KDB: enter: panic
[ thread pid 1 tid 100002 ]
Stopped at      kdb_enter+0x3d: movl    $0,kdb_why
db> bt
Tracing pid 1 tid 100002 td 0xc89efbc0
kdb_enter(c1065960,c1065960,c10b903b,c139f438,aef01785,...) at kdb_enter+0x3d/frame 0xc139f3f0
panic(c10b903b,1,1,1,c86c0032,...) at panic+0x14b/frame 0xc139f42c
dblfault_handler() at dblfault_handler+0xab/frame 0xc139f42c
--- trap 0x17, eip = 0xc0e93e07, esp = 0xc86bffbc, ebp = 0xc86c0032 ---
__qdivrem(0,aba80000,c10d,98600000,68c119,...) at __qdivrem+0x197/frame 0xc86c0032
db>