removing this kernel and reinstalling had no effect - same error.

Please attach the output of dmesg from a successfully booting kernel, as well as a digitial picture of as much of the backtrace as you can see on the failed boot.

Created attachment 1090694 [details]
dmesg output from good boot

Created attachment 1090695 [details]
failed boot backtrace

This attachment was manually created, so it may contain typographical errors.

I do not have a camera or cell phone to take a digital picture of the screen, which I believe is what was requested.

(In reply to Don Swaner from comment #4)
> Created attachment 1090695 [details]
> failed boot backtrace
> 
> This attachment was manually created, so it may contain typographical errors.

Thanks, that was helpful.

Looking at the versions you have, it seems like a patch added in 4.2.4 is causing your issue.  Upstream is already aware of it, and the fix is queued for 4.2.6.  Specifically it is:

commit ababae44108b0e94b58eef6cb5bd830bd040a47f
Author: Werner Pawlitschko <werner.pawlitschko>
Date:   Tue Oct 27 09:08:04 2015 +0900

    x86/ioapic: Prevent NULL pointer dereference in setup_ioapic_dest()
    
    Commit 4857c91f0d19 changed the way how irq affinity is setup in
    setup_ioapic_dest() from using the core helper function to
    unconditionally calling the irq_set_affinity() callback of the
    underlying irq chip.
    
    That results in a NULL pointer dereference for the rare case where the
    underlying irq chip is lapic_chip which has no irq_set_affinity()
    callback. lapic_chip is occasionally used for the timer interrupt (irq
    0).
    
    The fix is simple: Check the availability of the callback instead of
    calling it unconditionally.
    
    Fixes: 4857c91f0d19 "x86/ioapic: Force affinity setting in setup_ioapic_dest()"
    Signed-off-by: Thomas Gleixner <tglx>
    Cc: stable.org

4.2.6 is building right now.

kernel 4.2.6-200.fc22.x86_64 fixes bug

Thank you for testing.