Opening a non-existing block device currently yields an ENXIO error.
Doing the same for char devices produces the correct error ENODEV.

The attached patch fixes the symptoms.  Somebody with more knowledge
will have to decide whether there are any negative side effects.

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➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖