* Linus Torvalds <torva...@linux-foundation.org> wrote:
> On Thu, Feb 21, 2013 at 10:21 AM, Thomas Gleixner <t...@linutronix.de> wrote:
> >
> > This was a draft patch. I made it a WARN_ON_ONCE() already.
>
> Ok, good.
>
> I really wish we could just get rid of BUG_ON(). It was a bad
> idea, and it makes it easy for people to do the wrong thing.
> Sadly, we have tons of them.
So my old plan was to use a little bit of psychology.
Firstly, we could just turn BUG_ON() into a WARN() variant that
emits:
BUG: ...
while a WARN()ings emit:
WARNING: ...
and then we could introduce a new primitive:
CRASH_ON();
which would be used in the (few) places that really, really
cannot continue sanely and need to crash the box.
This naming alone would inhibit its use through two channels:
- Putting the word 'CRASH' into your code feels risky,
dissonant and wrong (perfect code does not crash) and thus
needs conscious frontal lobe effort to justify it - while
BUG_ON() really feels more like a harmless assert to most
kernel developers, which is in our muscle memory through
years training.
- CRASH_ON() takes one character more typing than WARN_ON(),
and we know good kernel developers are fundamentally lazy.
[ This is an arguably lazy plan that does not involve changing
the 10,000+ BUG_ON() call sites and does not involve the
re-training of thousands of mis-trained kernel developers who
introduced over 900 new BUG_ON()s in the v3.7->v3.8 cycle
alone (!). ]
So while I don't think we can win the war against BUG_ON(), I
think we can fight the lazy general's war: turn the enemy over
to our side and declare victory?
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
