64-bit kernel broken.

Run this test:
http://www.parisc-linux.org/~carlos/tst-sigqueue.c

On a 32-bit userspace, with a 64-bit 2.6.18 kernel and the test exits with 0.

carlos@firin:~$ ./tst-sigqueue
in f
pid = 1429
new thread: 1429
carlos@firin:~$ echo $?
0

Run it with a 64-bit 2.6.20 kernel and you get an error.

carlos@firin:~$ ./tst-sigqueue
in f
pid = 31148
new thread: 31148
expected PID 31148, got si_pid 1000
carlos@firin:~$ echo $?
1

Signal structure compat with a 64-bit kernel has been broken.

Any elite kernel hackers up to the challenge of fixing this regression? :-)
It's muddling our glibc test results...

Cheers,
Carlos.