david@l8s.co.uk said:
> I wonder if kdump understands the xxx_32 emulations at all??? 

This remembers me of something.
There is some confusion between use of sy_narg and sy_argsize
in the ktrace code. (If you ask me, sy_narg should be nuked completely
because it is worthless where 32-bit and 64-bit arguments are mixed,
eg off_t on 32-bit platforms. See my change to kern_ktrace.c rev. 1.76.)

The svr4_32 emulation code actually deals with conversion of a 32-bit
argument list into the 64-bit list understood by ktrsyscall(), see
sparc64/trap.c around line 2116. The problem is that this conversion
effectively doubles the size of the argument list, while ktrsyscall()
only expects sy_argsize==sizeof(struct netbsd32_xxx_args) and leaves
the other half uninitialized.
sy_nargs callot be used reasonably, as said, so probably the best solution
is to set up a ktrsyscall32() somewhere in sys/compat.

best regards
Matthias