I was trying to adapt a config file made on my old machine to use 4 cores instead of 2. I could not do it using make menuconfig.

For these numeric values, selecting one brings up an entry line containing the current value, if any. What I wanted was to delete the "2" and replace it with a "4". But I could not do the deletion, either with backspace or delete and could not overwrite either.

When I switched to make nconfig, I was able to enter "4" and delete the "2".

Did you raise a problem report so others aren't similarly affected ?.

I don't know how to. There are so many kernel lists! But I agree it ought to be reported somewhere.

Maybe there is a way to do the replacement in menuconfig but I just couldn't find it.

I'd try to confirm this by looking for a similar field in the menuconfig where you'd change a numeric value and see if you see the same behavior.

And what's the help show for number of cores? (As in when you highlight that field and hit the question mark) Perhaps that is tied to the CPU type selection (if any) and therefore it is a read-only field, because it knows the number of cores. Not sure, I've never tried to edit that particular setting, so just some suggestions.[Hands on hips/Lecturing stance]Did you search using the string "how to report Linux kernel bugs"?

Yes I checked help. But it's only about the meaning of the option. It doesn't tell you how to modify it. But I don't think this field is ever filled automatically; it was set to two because I previously built this kernel for an Intel Core2. I'm now adapting the configuration for a Pentium 4-core. Which btw isn't included in the list of processor types so I've had to use the general x86_64.

I haven't looked lately, I admit. I did look some time ago when I had a different problem and discovered that the main kernel.org mailing list has hundreds of posts every day and that you need to use one of the many others to get noticed. It's all too complicated for me!