An oops on a 2.5.25+ide24 system (with a few unrelated patches):
First cdrom_do_block_pc() invents a packet command and puts it
into rq->special.
Then cdrom_do_packet_command() wants to take it from rq->buffer,
which is NULL.
Oops.
Andries
[Apart from this oops: I have now used this kernel for many hours,
stressing various disks - the disk I/O part is solid for me.]