2.6.19: kernel BUG in hugepd_page at arch/powerpc/mm/hugetlbpage.c:58!

[Sonny Rao]

Hi, I was running a 2.6.19 kernel w/ 64k pages and running some
benchmarks with libhugetlbfs and got this BUG: 

kernel BUG in hugepd_page at arch/powerpc/mm/hugetlbpage.c:58!
6:mon>
6:mon> t
[link register   ] c000000000031024 .hash_huge_page+0x50/0x42c
[c0000002d92c7c90] c0000002d92c7d50 (unreliable)
[c0000002d92c7d50] c00000000002cf80 .hash_page+0x214/0x3bc
[c0000002d92c7e30] c000000000004834 .do_hash_page+0x34/0x40
--- Exception: 301 (Data Access) at 000000001009b0cc
SP (f33bc830) is in userspace

from this BUG_ON()

static inline pte_t *hugepd_page(hugepd_t hpd)
{
        BUG_ON(!(hpd.pd & HUGEPD_OK));
        return (pte_t *)(hpd.pd & ~HUGEPD_OK);
}

Has anyone seen this before?  A cursory search for hugepd_page and
this bug came up with nothing.

Sonny