amd64/99561: system hangs in FreeBSD AMD64 when writting ext2fs

[Dieter]

> Has anybody noticed something similar?

I don't recall if it was a hang or a panic, but yes.  Only occurs when
writing, reading has been okay.

> I do not know what is FreeBSD AMD64 problem when I compile something being
> in an ext2fs partition since with FreeBSD x86 I didn't experienced similar
> behaviour.

That is a major clue.  It is probably an LP64 bug.