zfs crash on amd64

[Adam Hamsik <haaaad%gmail.com@localhost>]

Hi folks,

I would like to ask you for a help with one strange issue on a amd64  
with a zfs. On amd64 zfs panics during zpool create. Backtrace + panic  
message can be found here[1]. I got several other panics(different  
backtrace) but most of them was somewhat related with SHA256Transform.

I have added some printfs to the zio_checksum_SHA256 and everything  
looks fine, but when panic happens H[0] is NULL. I'm really not sure  
how is this possible, but I have checked it twice. PAnic happens here  
[2]. Panic instruction is this

movl 0(%rax), %eax

I checked rax register from ddb and it is set to 0, which is strange  
because when you look at debug printfs socend address printed in it is  
address ofH passed to SHA256Transform. I talked with joerg@ and he  
suggested that it can be some problem with stack overflow on amd64.  
This problem can be seen on i386 on machines with >3Gb. I would like  
to enlarge default kernel stack size on amd64 to try to fix this  
issue. Anyone has an idea how can I do that ?

I'm using DIAGNOSTIC modules build with -O0 -g.

[1]http://yfrog.com/e9screenshot20091102at120p
http://nxr.netbsd.org/xref/src/external/cddl/osnet/dist/uts/common/fs/zfs/sha256.c#97

Regards

Adam.