Re: [RFC PATCH 8/9] debugfs: defer debugfs_fsdata allocation to first usage

From: Johannes Berg
Date: Wed May 03 2017 - 01:44:15 EST

On Tue, 2017-05-02 at 22:05 +0200, Nicolai Stange wrote:

> > So either you could return some valid ops (perhaps
> > debugfs_noop_file_operations although those don't have .name or
> > .poll, so it doesn't cover everything), or you can just BUG_ON()
> > here directly, saving the incomprehensible crash later.
> The purpose of that WARN_ON() there was to turn a potentially
> incomprehensible crash into a comprehensible one ;)
> In order to avoid a new BUG_ON(), what about keeping the WARN_ON() as
> is and returning NULL instead of the garbage? That would crash
> current on first access and the earlier warning would hopefully give
> some clue?

Yeah, I guess that might work. Probably less harmful to the system than
a BUG_ON(), but I still operate under the assumption that there might
actually be something mapped at NULL - not sure if that's still true.