It's a plain old Linux kernel bug: it returns EIDRM when it really ought
to say EINVAL, and apparently always has. The surprising part is really
that we've not seen it many times before.
Kudos to Michael Fuhr for thinking to write a test program investigating
whether randomly-chosen IDs would
I wrote:
I'm going to generate a smaller test program showing this and file
a bug report at Red Hat.
Filed as
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=246509
in case anyone wants to track it. (I suspect the Red Hat kernel guys
will just bounce it upstream, but that's their call not
